It’s nice to know that ASE is keeping track of how long the technicians that participate in their program have been certified. It’s even nicer that they recognize these technicians with a medal that has a magnetic backing so you can stick it on your toolbox.

When it comes to being an automotive mechanic there is no substitute for experience. The longer you turn a wrench the better at it you become. This is mainly because every day you learn something new. These learning experiences build up in your brain and you are able to call upon them when needed.

Taking ASE tests

25 year auto repair career

This ASE 25 year medallion couldn’t have come at a better time. This is because it is once again time to register for my recertification tests in November. After 26 years of being a mechanic I feel worn out with all the test taking and back breaking work.

This medallion seems to have rejuvenated me to some extent. I have about 12 certifications that are due to be renewed over the next two years. This is out of the total of about 16 that I currently hold.

Although I am not looking forward to studying and taking the tests after a long day of working it is at least nice to know that someone is keeping track and does care about the hard work it takes to remain certified.

What is the ASE 25 year medallion all about

ASE 25 Year Medallion

The 25 year anniversary medallion was designed to recognize and thank technicians who have demonstrated dedication to professional automotive service through 25 years or more of ASE certification. Since 1972, more than 1.6 million people have registered for ASE testing. About 21,000 technicians or a little over 1%, have qualified to receive the medallion as of 2008.

Some mechanics ask why they have not received the medallion. This is most likely because your certifications lapsed at some point during your career. To receive the recognition ASE will count the total number of years you have been certified, not how long ago you were first certified. Also note you must be currently certified to qualify.

You can have gaps in your certification history and still receive the anniversary medallion. But the total number of years certified has to be 25 or more. And again you must be currently certified in at least one area. If you have let all of your current certifications lapse, you don’t get credit for those expired years. If you later recertify you will continue to add to your total years of certified service.

If you’re interested in taking ASE tests I put together a page that contains some helpful tips on how to prepare for the tests. I also made available some ASE study guides. If you are looking for automotive information and articles this next link will take you back to the auto repair information blog.

standard timing light

Setting ignition timing on cars today is usually not required. I still own 2 timing lights and find it necessary to adjust the engines timing on rare occasions. This is only possible on vehicles that still have distributor type ignitions.

Although most vehicles nowadays have direct ignition my 2004 Chevrolet Blazer with a 4.3 L V-6 engine still has a distributor and you can adjust base timing. Remember only engines equipped with a distributor may need to have their ignition timing set or adjusted.

Although the computer still controls ignition timing on distributor ignition, having the base timing correct is critical for proper performance and fuel economy. If the base timing setting is wrong the advance curve settings can also be wrong.

On modern vehicles with distributor type ignition the timing is advanced as rpm’s increase. These controls are the function of the computer and the curve is not adjustable. To set the base timing there will be different procedures to follow to disconnect the computer from the distributor so that the setting can be adjusted.

Procedures for setting ignition timing

Each vehicle manufacturer will have slightly different versions of ignition systems deployed on their vehicles you should always refer to an auto repair manual and also take a look at your emissions service label that is usually mounted on the radiator support.

In some cases the emissions service label will provide a procedure for disabling the computer’s control of the timing so that proper reading and adjustments can be made. Some advanced scan tools are able to take a reading of the ignition base timing. When you disconnect the distributor to make adjustments that will no longer function. This is why a timing light is still needed for this operation.

To check the base timing a strobe light is aimed at the ignition timing marks. Timing marks are usually located on the crankshaft pulley but in some cases can be located on the flywheel side of the crankshaft. Again you’ll have to check your service manual to find out not only what your base timing settings should be but also where the timing marks are located.

Usually an engine is timed so the number one spark-plug fires several degrees before the piston reaches top dead center. When the timing light is connected to the number one spark plug wire and will flash every time this wire is fired. When pointed at the timing marks it may look like a strobe light that will actually freeze the spinning timing marks as it passes the scale so that your eyes can detect it. Yes it’s like a disco club.

Problems with setting ignition timing

advanced timing light

It is important to remember that most computerized and spark control systems will use some type of knock sensor to retard the ignition timing when ping occurs. Engine ping is also known as incorrect detonation. This is really important on today’s modern aluminum engines.

In some cases when the cylinder detonates at the wrong time extreme temperatures can be the result. These temperatures can be extreme enough to melt aluminum cast engines. This is why the knock sensor will automatically retard the timing and attempt to stop the detonation and prevent engine damage.

Messing around with your cars engine timing should only be attempted if you have done some research about the procedure and have some do-it-yourself driveway mechanic skills. When in doubt take the vehicle into your local auto repair shop and have this procedure performed by professional.

I hope that you found this article helpful even if you decide not to attempt to adjust your own ignition timing. Knowing more about the subject can usually be helpful in either dealing with your auto repair shop or identifying that there is a problem to be addressed. I have a few more articles about this subject on the auto repair information blog.

Timing Tester

Improper ignition timing can cause several car problems. Anything from hard starting to lack of power might be traced back to the root cause of incorrect base ignition timing.

In rare occasions I have also seen a hard start condition from this as well. Often when people are having poor performance from their engine they may wonder if it is an issue with the engine timing.

You have to remember that poor engine performance can also be caused by poor compression, overheating, incorrect valve timing that can be caused by a timing belt that slipped one notch. Clogged catalytic converters and probably about 20 other things can also cause this condition.

How to test for improper ignition timing

When the ignition timing is not correct there are a few tests that can point to the car problem. The main symptom of a timing issue would be incomplete combustion at different engine speeds. Incomplete combustion can cause an excess of oxygen in the exhaust stream.

In this case the powertrain control module will try to compensate for this imbalance of the air fuel mixture by changing the injector on time to straighten out the mixture. If you have a scan tool that can read the data stream you can pull up the fuel trim mode and see if the computer is forcing the injectors to stay on longer or shorter.

If you have exhaust gas analyzer such as the kind that is used by automotive shops and inspection stations you can sample the exhaust stream and read the amount of oxygen. You can also pull up the oxygen sensor data stream on your scan tool and see if the voltage is changing properly.

Vacuum test for incorrect timing

The vacuum gauge is inexpensive and handy device that can quickly perform a few tests that can help diagnose lack of power problems from clogged exhaust among others. Incorrect ignition and valve timing also affects manifold vacuum readings. If you connect your vacuum gauge to a strong manifold vacuum source and low readings are observed you can adjust the base timing to see if the readings are able to be brought back into specifications.

Another telltale sign of a timing problem would be excessive engine ping. Engine ping is referred to as cylinder pre-ignition. This is when the air fuel charge is ignited at the wrong time. If it is ignited before top dead center it can cause the valve train to generate a noise that is known as engine ping.

In most cases engine ping is caused by timing that is too far advanced. If the timing is too far retarded the most likely symptom would be a hesitation lack of power and very poor fuel economy. I am working on an article about using a timing light to check for improper ignition timing. It should be ready for my next weeks post here on the auto repair blog.

Distributor Cap and Rotor

This post is for people that still have a distributor cap and rotor ignition like me instead of the more modern ignition systems such as direct ignition or coil on plug type systems. Some vehicles including my 2004 Chevrolet Blazer still use a distributor cap and rotor to fire off their spark plugs.

This type of ignition system can cause car problems like an engine misfire or shudder under load. Caps and rotors have been around for a long time and for the most part they are extremely reliable. There is no shame in having a distributor ignition.

Sure your friends may say your vehicle is old-fashioned as they point and laugh at you while you’re in the parts store buying replacement parts. When this happens remind your friends that your cap and rotor only cost $28 while their individual coil that has failed might cost $200. A direct ignition coil and module assembly could cost around 350 bucks.

Problems with cap and rotors

The reason I’m writing this article is that I continue to see a common problem that develops on vehicles that use a distributor cap and rotor ignition systems. This would be moisture and corrosion that can build up inside. Back in the early 1990s the 4.3 Liter engine was extremely susceptible to this type of corrosion.

Bosch Distributor Cap

Technical service bulletins were created by General Motors to make technicians aware that the vent on the base plate could become clogged and accelerate the moisture buildup and corrosion inside the distributor. Not only would this damage the cap and rotor but it could also affect the ignition module.

The module connections can turn green and even disintegrated if the problem is not addressed. The technical service bulletin informed technicians that they needed to check that the vent screen and the base of the distributor was clean and allowing moisture to be vented out.

Just about every distributor that I checked in the early 1990s was experiencing this problem. When the cap was removed it looked like it snowed inside the distributor. Often it wasn’t until the vehicle was towed in for a no start condition that the problem was identified.

More problems with rotors and distributor caps

You should also make sure the distributor cap is properly seated on the base plate and all clips and screws are tightened securely to provide a good seal to keep moisture out. It is a good habit to inspect the distributor cap and rotor and check for physical damage and also corrosion build up inside.

Other types of damage that needs to be inspected would be electrical damage from high voltage. You can check for burned metal terminals and also carbon tracking inside the distributor cap. Carbon tracking is the formation of a line of carbonized dust between distributor Terminals or between a terminal and the distributor housing. Carbon tracking indicates that high voltage electricity has found a better path over or through the plastic.

The result can be car problems such as a misfire or shudder under load due to the spark plug firing at the wrong time. You can check the outer Towers and metal terminals for defects. Although distributors are usually well protected sometimes you find cracked plastic that may warrant replacement. You should also inspect the distributor rotor for a buildup of corrosion on the tip that passes voltage to the terminals of the cap.

Although you can take an emery board to the tip of the rotor to clean it I usually recommend replacing it because a distributor rotor is only about six dollars. For more information about solving car problems and the latest posts from this auto repair blog visit the homepage from that last text link. I recently wrote a page on my other website about no starts and no spark. If you have a no start condition and are interested in learning how to test for spark take a visit.

High Performance Coils

The coil on plug ignition system has been out for quite a while and seems to be gaining in popularity. Although the system does seem to be extremely reliable I have ran into a few problems with individual coils. Note that I have some replacement and high-performance ignition parts available below the article.

The problems I have seen included an intermittent rough engine idle that would set a check engine light code for random misfire. I have also seen a few completely dead coils that set misfire codes for specific cylinders. If you set a p0303 code this would indicate a malfunction needs to be diagnosed on the number three cylinder.

In my worst-case scenario I had an extremely intermittent engine miss on a Ford van that would only misfire when the engine was extremely hot. It set a code for a random misfire which did not help me narrow down which cylinder had the problem. This was a V10 gas engine and the cost of replacing 10 coils just to find the bad one would have been huge.

I tried purchasing one new coil and then rotating it through each individual cylinder to see if the problem was solved. Unfortunately the engine misfire could take up to an hour to resurface so my method of switching out the coils with a known good one was time-consuming.

Ford Coil On Plug

Before I started switching out the coils with the known good one I did take the time to use an ohmmeter on each individual coil to test resistance. Each one tested within specifications even though there was a problem with one of them when Hot.

I finally discovered which coil was causing the intermittent misfire by searching through Ford technical service bulletins. Although it did not tell me which cylinder was going to have the problem it did indicate that a hairline crack could develop on the bottom side of the coil and cause this condition?

I removed all of the coils and inspected the back sides of them with a magnifying glass. A tiny hairline crack was observed on the cylinder closest to the driver. I took my one good coil and put it in that cylinder and I have not heard from the driver since. As you can see finding out which coil has the problem can sometimes be challenging.

What is coil over plug ignition

Coil to Plug Boot

The operation of a coil on plug ignition system is basically the same as that of any other. The main difference is that these systems have an individual coil for each spark-plug. The two most modern designs of this kind of spark system would be the coil on plug (COP) and the separate coil per cylinder.

The main difference between these two types of systems is revealed in their description. The separate coil per cylinder system will have a short spark plug wire running to the plug. The coil itself will usually be mounted just above the plug or nearby at least. The coil on plug system has a boot that directly connects the coil to the plug.

They say that the main advantage of these new systems is that having one coil for each spark plug allows for more time between each firing. This can increase the life of each individual coil as it is allowed to cool between firings. This off time is also used to increase the output of the spark by charging the coil while it waits for the orders to fire.

The (COP) ignition system is controlled by the PCM or power train control module. The crankshaft or camshaft position Sensor provides the input to the PCM. The powertrain control module is programed with the firing order for the engine and determines which ignition coil should be fired at the right time.

It would seem that the advantages of these new ignition systems outweigh the troubles that you may encounter when trying to hunt down one single bad component in the system. I have seen many engines with these types of systems go to the junkyard with no problems at all. This may not provide any comfort to you if you are having a random misfire and are having problems locating the bad coils.

In my opinion purchasing a subscription to an online auto repair manual helped me find the problem that I discussed above. I know a lot of people search on the Internet for free information but sometimes it is worthwhile to pay a few bucks to save a couple of days of labor. I wrote an article on this blog about free auto repair manuals. Looking for more of the latest posts? This next link will take you back to the auto repair blogs home page from this post about coil on plug ignition.

Fog Light Kit

Note at the end of this all about fog lamps article will be links to some of the most popular fog light kits and replacement halogen bulbs for factory installed systems. But first didn’t you ever wonder about your cars fog lights. Why they are constructed different than headlights. Why they are mounted in positions that are far lower than regular headlamps.

When I first started to drive at 16, no cars had factory mounted driving lights. This was an aftermarket accessory that I quickly added to my vehicle so it would look cool. To my surprise not only did they look cool but they actually came in handy. I found myself driving through foggy areas often as I lived near cranberry bogs in a low lying area of New Jersey.

A side note when you are adding auxiliary lights you must make sure that your alternator and wiring are heavy duty enough to handle the increased wattage. In the case of my 1974 Dodge charger the fog lights were too much for the standard wiring and charging system. After an electrical fire that melted all the lighting circuit components I upgraded the alternator and installed new heavy gauge wiring. After the upgrades all was good.

Difference between fog lights and headlights

Ordinary headlights do not penetrate the fog very well. The focus of a powerful beam of light directly at the fog reflects most of the light back to the driver. You can verify this by switching from your high beams to your low beams on a foggy night. You can see fore yourself which one actually provides the best distance of site.

Wide beam fog lamp

I’m not a scientist but I believe it’s because the fog is made of water molecules and these tiny droplets of water are what actually reflects the beam of light back in the drivers face. Fog lights in most cases use halogen bulbs but instead of using a wide powerful beam they attempt to sneak a flat beam of light under the blanket of fog. This is one of the main reasons that fog lights are mounted as low as possible on the vehicle.

Fog is actually like a cloud that hangs near the ground. This is often generated from temperature differentials. Cold air meets the warm ground or body of warmer water for example. So much like clouds in the sky fog forms when the air becomes saturated with moisture. As a result water forms out of the air into a fine mist of water droplets. Fog can get very dense and obscure visibility quickly as it forms with little warning.

H3 Halogen Bulb

Nowadays more often than not fog lights will come standard with your vehicle and not needed to be added using aftermarket parts. In the case of my current vehicle which is a 2004 Chevrolet Blazer my fog lights are factor installed.

On my blazer you can only use the fog light if the headlights are on the low beam settings. If your fog lights are on and you switch on the high beams the fog lights are automatically turned off. In my example above when you are trying to drive in foggy conditions the brighter your headlights are the worst your vision becomes.

My Chevy Blazer is set up so the fog lights only operate if the headlights are in the low beam setting. Replacement halogen bulbs can vary greatly in price from store to store. My Blazer uses the H3 halogen bulbs. I have provided a link to it below for your convenience.

For more of the latest articles on this blog this next link takes you back to the homepage from this page about fog lights. If you’re interested in more articles about technical subsystems related to cars I have a section dedicated to automobile technology you might find interesting.

300ZX AC Problems

I had a few 300ZX air-conditioning problems with my 1988 Z. in case these are problems that are inherent in these vehicles I will describe them below. When I got this car it had r12 Freon in the system as you would expect from an older vehicle such as this.

Me being an automotive mechanic that has converted many systems, I was prepared to do the same to this vehicle. I did have a 1 pound can of r-12 Freon that I used to bring the system up to its proper level when I first got the car. I was expecting that someday I would have to convert the system to the new R-134a. To my surprise I did have problems with the air-conditioning system but never had a refrigerant problem so I never converted the system.

I have put a page together on my you fix cars website that has more tips and directions for people that want to convert from r12 to 134a. There is more to the procedure then just dumping one and installing the other. In fact if you do not follow the recommended procedure your air-conditioning system will probably not blow cold for long.

Nissan blower motor problems

My 300ZX was equipped with Nissan’s continuously variable airflow control. This means that there were more settings than just medium-low and high. And the system was actually quite complicated. There was a fan control amplifier which utilized a series of transistor-based circuits that continuously controlled the airflow blown out by the blower.

Blower motor pushing air through evaporator

This allowed for a selection of infinitely variable airflow rates. The fan control amplifier is housed in the blower motor case itself. There is a heat sink radiating plate mounted on the amplifier assembly and it is placed in the airflow of the blower motor to provide cooling to the transistors to prevent electrical heat failure.

When my 300ZX reached about 12 years old I started experiencing intermittent airflow operation and I could hear the blower motor kicking on and off. When I pulled out the fan control amplifier I didn’t see any melting or actually any problems but it was the culprit and needed to be replaced. I got the replacement part from the junkyard and never had any other blower motor problems with the car.

Nissan AC problems

I did have 300ZX air-conditioning problems that were not a Freon related issues. At first I thought it was, because the problem was the air would start off cold and then get warmer the longer you used the AC system. This is a typical symptom of an evaporator freezing up. One day I ran the air-conditioner until it started to warm up and I pulled the evaporator cover off to find a solid block of ice.

It’s funny that when the evaporator is frozen solid into a block of ice that the air actually gets warmer. But it is true because the airflow through the cooling fins is reduced and diverted around the evaporator assembly instead of flowing through it.

Nissan AC expansion valve

On a 300ZX air-conditioning system the compressor cycles on and off to maintain the proper evaporator temperature. When the evaporator temperature falls below a specific point the Thermo control amplifier interrupts the compressor operation by disconnecting power. When the evaporator temperature rises above the specification power is restored to the compressor.

The late 80′s Nissan 3 L V-6 air-conditioning system uses an expansion valve with a capillary tube that provides the temperature input from the evaporator. On my 300ZX the capillary tube leads to a bulb on the end that attaches via a clip to the evaporator fins. I’m not sure how it happened but it became detached and was just laying in the evaporator case and was not providing the proper input temperature. I cleaned the temperature bulb and reattached it to the evaporator fins and the problem was solved.

On this auto repair information blog I have written a lot about my 300ZX and the repairs that were needed. This was one of my favorite cars but also required the most work out of any automobile I had ever owned. It was also my first Nissan so it taught me a few lessons about Japanese cars. I have also written many air-conditioning articles and you can head back to the main page and see the latest auto repair blog posts.

AC Compressor

When Car AC repairs are required one of the worst-case scenarios is having to replace the AC compressor due to an internal failure. When I say internal failure I’m talking about the compressor coming apart inside and spreading metal throughout the air-conditioning system.

Often both professional and driveway mechanics will just try to replace the compressor by bolting on a new part. This is an invitation to further repair and ongoing problems with the air-conditioning system. The small metal pieces that are hiding throughout the lines and other components will circulate and continue to cause problems.

Proper compressor diagnosis

In most cases when a compressor suffers internal damage the telltale sign would be the noise generated from the compressor itself while the clutch is engaged. You do want to take some time and verify that the noise is actually coming from the AC compressor and not another belt driven accessory.

Before condemning the compressor to be the faulty component it is a good idea to confirm this by fully charging the system and take some pressure readings. When a compressor has internal damage it is unable to pressurize the system properly.

Normal pressure readings on a summer day would be about 35 PSI on the low side. And about 150 to 200 PSI on the high side. These pressure differentials are created by the compressor itself. If the low side pressure is high and the high side pressure is low with a full charge this is a sign of a defective compressor.

AC compressor replacement procedures

The problem with replacing a bad compressor that is damaged internally is removing all a little metal particles from the system. Often both driveway and professional mechanics would like to just blow compressed air through the lines in the hopes that all of the pieces will be dislodged and removed.

The reason this doesn’t work is because the system contains an oil charge. This oil sticks to the inside surface of all of the lines and tubes. The metal particles then stick to this oily film. This is why the proper procedure is to use a liquid flushing agent to flush the AC system.

The AC flush chemical has similar properties to brake clean. When the liquid is forced through the system the oil is washed out and the alcohol base of the AC flush will dry the interior surfaces of the lines. With no more sticky oil film holding the little metal particles they are easily removed.

AC Dryer

One of the components that cannot be completely cleaned with the AC flush procedure is the receiver drier. This component should be replaced along with the orifice tube when you are replacing the AC compressor itself. Flushing the AC system will not remove metal particles from the orifice tube or the receiver drier.

If someone replaces your AC compressor for you make sure that you’re getting your money’s worth and that they are performing the proper procedure. Ask them about how they will flush the system and how long they will guarantee the replacement of the compressor. This will often force them to take the extra step and do the job properly.

Feel free to visit my you fix cars website for a detailed list of the steps that should be followed when replacing car ac compressor. Or you can return to the auto repair information blog homepage for more of the latest posts to this blog.

Beam Torque Wrench

Professional mechanics, driveway mechanics and most people that work on cars hate taking the time to torque bolts properly. As a professional mechanic myself I don’t like it either. First you have to break out your torque wrench and maybe even get it calibrated.

Next you have to find the actual torque specification in an online car repair manual for the bolt that you are going to tighten. Then you’ll have to take extra care and get your torque wrench on the bolt and finally torque it to specification. This is a lot of effort when you can just put a wrench on that very same bolt and just pull on it for two grunts and a groan.

Not applying proper bolt torque would be considered a shortcut that can reduce the quality of the car repair and may cause a repeat failure or additional repairs to be performed. This is more critical in some areas such as intake manifold bolts. If these are not torqued properly they can allow coolant to run inside the engine and damage expensive internal parts.

Add to this the fact that many modern aluminum intakes now use composite gaskets that are primarily made of plastic and this increases the necessity for proper bolt torque. On some of these modern aluminum intake manifolds the actual torque specification is very low and the pattern that you tighten the bolts down in is extremely critical.

Why do we have to torque bolts

All metals whether they are aluminum, steel or even titanium have some elastic properties to them. This property means the bolt can be stretched and compressed. When the bolt is stretched a clamping force or holding power is created due to the bolts natural tendency to want to return to its original length. This can stop the bolt from backing off even if it is exposed to lots of vibration.

Like a spring the more bolts are stretched the tighter it becomes. Keep in mind that a bolt can be stretched too far. When you have gone past this point of no return you can often feel it in the wrench. When you reached this point the pressure applied to the wrench turns the bolt further with less effort. This is your telltale sign that you have gone way too far.

Often this is when the head snaps off and leaves an extremely tight bolt with no head stuck in a hole. When this happens the repair time is increased greatly along with the troubles that may be generated by drilling and removing the broken bolt.

When you compare the amount of aggravation generated by breaking a bolt compared to the time that it would take to look up the proper torque specification and set up your torque wrench you are much better off doing it the right way.

3/8 drive click torque wrench

After being a mechanic for 25 years most often I would use my half-inch torque wrench. But now it seems that I use my 3/8 drive torque wrench even more. I have also recently had to add an inch pound torque wrench to my tool-set.

This has been an ongoing trend of bolts that are torque to a lighter specification. The good news is the cost of these tools has continued to come down. Visit my auto facts website for more information about torquing bolts and access to inexpensive bolt torque wrenches.

For more of the latest posts to this website you can get back to the homepage from this next link. I add new articles about once a week to the auto repair information blog.

Defroster grid repair kit

Rear window defroster problems can cause poor visibility through the rear glass and on some models the side view mirrors are connected to the same system. This article covers a few of the common problems with electrically operated defroster systems as well as a few facts about how it operates.

Whether you call it a window defroster, deicer or defogger what were all talking about is heating the rear glass to remove moisture particles that can collect on the glass and reduce visibility. The major components of the rear window defroster on most models will include a manually operated on off switch, one or two relays and the heating elements on the glass surface.

The front windshield uses forced air that has had the moisture removed from it by the air conditioning evaporator to dry the front and side windows with warm low humidity air. This is a more efficient method than the heated grid that is commonly mounted on the rear window glass. Therefore slower defogging should be expected.

Common rear window defroster operation

The electrical rear window defogger is one of those systems that operate basically the same on most makes and models. You may find a few models that operate differently but for the most part standard operation is the same.

By pressing the rear window defroster switch you will energize a relay that sends power to the rear heater grid assembly. On many models full battery voltage is sent to the rear grid. On models with heated side mirrors voltage may also flow to these at the same time.

On most of the systems that I have worked on I find that they are equipped with some type of timing device. Often this automatic rear window defroster timer is set for about 10 minutes. This is to prevent overheating of the glass element. It’s not very common but I have seen rear window defroster problems caused by a timer malfunction. It can heat the glass until it cracks or not turn it on at all.

Even though some rear window defrosters have this automatic shutoff feature it is still wise to turn it off manually after it has completed its task of removing fog and moisture from the inside of the glass. There is no reason to continually send voltage to the heating grid and when this is switched off more efficient battery charging is accomplished.

Common rear window defroster problems

Tester and repair kit

One of the most common problems with rear window defrosters is physical damage to the heating grid that is glued to the rear glass. Damage can be caused by objects rubbing across the inside surface of the glass or in some cases by overzealous cleaning of the inside glass surface using harsh chemicals.

When working at new car dealerships many times we found that the temporary tag that was stuck in the back windshield was glued over the defroster grid. When the customer received their permanent tag and remove the temporary they wound up damaging the electrically heated grid.

When a segment of the grid is damage it opens the circuit. This can cause the grid to become inoperative from the break point forward. An open spot in the grid can be found by using a test light or meter. With the defroster turned on voltage should be present at all points of the grid.

With one side of the test light grounded you can lightly touch the point of the test light to the grid to test for voltage. It is best to start at the voltage connection and work your way towards the ground side. If there is no voltage at all then it will be time to test the switch, fuse and circuit breaker along with any system relays.

If you do find open grids often they can be repaired with a paint like compound that is available at most part stores. For more information about car accessories and their problems you can visit the auto repair information blog homepage from this page about rear window defroster problems.

Honda Power Mirror

Power mirror problems are quite common because these automotive parts are exposed to the elements as well as stick out from the vehicle and are subject to impact damage. Factory original replacement power mirror parts can be very expensive.

Although I am not a supporter of cheap aftermarket automotive parts this is one area of the vehicle that I will make an exception. Listed below will be some of the most commonly searched for replacement power mirror parts such as the master power switch and the complete mirror motor assembly itself.

The nice thing about these systems is that they are very similar between car lines and even models. A VW electric mirror system is not that different from the one installed on my Pontiac Grand Prix. Before we get to replacing parts let’s discuss some of the more common power mirror problems.

Power mirror parts problems

Power Mirror Switch

Some power mirror parts that I see the most failure in would be the master control switch and stripped nylon gears on the electrically operated motor. In the case of my old Pontiac Grand Prix the power master switch is located on the armrest of the driver side door panel.

With the way that the roof is designed anytime it rains and I crack the driver side window water drips off of the roof line and directly into the power mirror master switch. After a few years of this happening to switch itself which is rather delicate compared to the other switches on the vehicle can become corroded and provide intermittent operation.

In some cases you are able to disassemble the switch and clean the electrical contacts. But again this switch is made rather delicate and sometimes the disassembling of the switch will lead to eventual replacement of it. The tiny springs and contacts can get lost and in some cases the plastic will just break apart and you will not be able to put it back together.

Power mirror not working

In many cases when you operate the power mirror master switch you can hear the motor running but the glass doesn’t move. The motor controls the movement of the glass in most cases with a series of small nylon gears. If the mirror is binding then the nylon gears will start to slip and eventually the little teeth will wear off.

VW Power Mirror

Back in the old days they used to offer overhaul kits and we use to replace the gears and motors as necessary. Nowadays it is more common that the manufacturers and aftermarket companies will offer a complete replacement that includes the new glass, the housing and all internal parts including a new motor.

In my opinion this is really the way to go using the aftermarket power mirror parts in a complete assembly. In most cases power mirror assemblies whether they be driver-side or passenger-side are relatively easy to replace. On many models you may have to remove the door panel to gain access to the retaining bolts.

Having a properly operating power mirror assembly is more than just a convenience. When properly adjusted these mirrors give you a view of what’s happening around you with simple eye movement to the left or right. When you have power mirror problems and you’re not able to adjust them on the fly you can have an increase in the area that you can’t see. These are most commonly known as blind spots. These blind spots can get you into trouble when you are switching lanes on the freeway.

If you are interested in more auto repair information articles this next link will take you to the blog’s home page. You can review more of my latest posts and I usually add new ones about once a week. Visit the auto repair information blog from this page about power mirror problems.

Me working on a diesel engine

Diesel fuel is a petroleum product that is not as popular in the United States as it is in other countries. As a resident of the United States and a strong believer in the benefits of diesel fuels I hope that the North American continent will someday embrace this type of fuel.

One thing that can be said about diesel is that it contains more energy per gallon than gasoline and therefore can be considered more efficient. The engine that burns this type of petroleum produces much more torque at lower RPMs because of high compression chamber ratios.

This makes it a perfect choice for trucks and trains that haul heavy loads and that will require massive amounts of torque to get that load moving.

The difference between diesel and gasoline

The fuel in a gasoline engine is ignited by a spark plug. The diesel engine uses its own high combustion chamber pressure to compress the fuel until ignites on its own. Gasoline is extremely flammable compared to diesel fuel.

The flammability of gasoline is measured using the familiar octane rating. Diesel fuel also has a measured ignition quality known as the cetane rating. Much like the octane number the cetane number is measured in a single cylinder test engine with an adjustable compression ratio.

The higher the cetane rating the shorter the ignition lag time before it is ignited by the compression stroke. An average cetane rating that can be found at the pump would be around 50. Whereas the average octane rating of gasoline would be around 87 on regular grade at the pump.

Different grades of diesel fuels

Minimum quality standards exist for diesel fuel grades. The two common grades of diesel fuel available would be number one diesel and number two. Number two is most commonly found at the fuel island in the local gas station. Number one can be blended with number two to improve starting in cold weather.

Different areas will blend the two fuels at different rates depending on how cold the climate is. The number two grade is more efficient and contains more energy. In winter months when number one is blended in it can actually reduce fuel economy.

Bio diesel fuels to me are the most interesting. These can be made from recycled restaurant grease and many different types of vegetable oils. Bio diesels fuels can be used all by themselves are blended with number one or number two grade fuels. If it can be produced cheap enough and then blended it can have very positive effects on the cost per mile.

In most cases to use a blended Bio diesel no engine modifications are required. It also does not affect the vehicles overall torque or horsepower and in turn does not reduce the vehicle’s ability to carry a payload. Research has also shown that emissions from blended Bio diesels can be lower compared to the number one and number two grade types.

As we all know the world needs to get off of fossil fuels. Solar, wind power and other cutting-edge technologies may take decades to get off the ground. Diesel fuel may be exactly what we need to bridge the gap to the future. Read more articles from this auto repair information blog. Or this next link will provide a bridge to more information about alternative fuels.

Power Window Motor

Power window problems on cars and trucks could be considered one of the most annoying problems you could have on an automobile. When you think about it how often do you actually operate the power windows on your car.

When you roll up to the drive-through window at your favorite fast food restaurant or you are going to pay a toll I’m sure you would like your window to operate properly. Many times electric window operation can become intermittent. This is even more frustrating than if it stopped working altogether.

When you have intermittent operation the tendency is to put off repair of the system until either the problem gets worse or the Windows stops working all the time. From a safety point of view you really shouldn’t put off repairs because you never know when rolling up or down that window will be important for safety reasons.

Power window systems

Power Window Parts

The power window system happens to be one accessory that really doesn’t vary that much between vehicle manufacturers or car models. The major components of an average system would be the master switch, the window lift motor, circuit breakers and relays, and the wiring that ties those items together. Oh I forgot the glass itself.

Often when the window stops working people ask me where the fuse is. Most modern power window systems do not actually have a fuse. It is more common to find a circuit breaker protecting the wiring and electrical components. A circuit breaker will automatically reset if the system overheats or pulls too much amperage.

In addition to the main circuit breaker usually there is an internal circuit breaker to protect each individual window lift motor. If one of the window switches is held too long or the window is obstructed the circuit breaker will automatically open to prevent damage to the motor.

Common problems with power windows

Master Switch

I diagnose a lot of these power window systems. The two most common problems that I find is either a defective window lift motor or a problem with the master switch. To break it down even further it is the driver side window motor that I see fail most often.

The simple fact is that the drivers side front door window is operated much more than any of the other Windows on most vehicles. This is also true with the master switch that is usually mounted on the drivers side door panel. The master switch gets more use than the other switches in the vehicle.

On my own personal vehicle the master switch is mounted flat on the driver side armrest on the door panel. I have had problems with the master switch because of its location. Water from the roof drips right onto the switch when the window is down or even partially opens. This poor design led to heavy corrosion built-up inside the switch.

I was able to save myself from replacing the switch by removing and disassembling it. I got myself some electrical contact cleaner and was able to remove all of the corrosion. I have to perform this procedure about once every two years because of this master switches poor location.

Diagnosing electric windows

Just because the driver side master switch and the driver side window lift motor are the most common failures this doesn’t mean that you will have those exact problems. Many other parts of the system are capable of failing.

When you’re starting your diagnosis of a power window system it is best to determine if the whole system is not working or maybe it’s just one window from one switch. If nothing works in the system the place to start would be with the master control switch or the main system circuit breaker.

If only some of the Windows don’t work and others do you would want to check parts that are common to the windows that are not working. From an electrical point of view you may need a wiring diagram for your specific automobile to determine what electrical parts are in common.

As an example let’s say that the right rear window is the only window not working. It does not work from the master switch or the switch on the right rear door panel. In this case it would be time to remove the door panel and inspect the power window motor that runs that window. Again an online auto repair manual will provide step-by-step diagnostic instructions to determine what the failure is.

Car Airconditioning Compressor

I get a lot of questions about car air conditioning systems not blowing cold enough. Especially during hot humid summer days. Most people would like to see frigid cold air blasting from their small dash vents instantly upon request.

Remember when your car has been baking in the sun heat is stored up in large quantities and must be removed before it starts to feel cool inside. But what if the air does not seem to get cold after 5 minutes or so?

There are many factors involved that affect the actual output temperature at the dash AC vents. To follow will be a few examples of common problems that I find when inspecting a car air conditioning system that is not performing as well as it should be.

Without a doubt the most common problem that I find is an incorrect Freon charge. The amount of Freon in the system is extremely critical. The manufacturer installs the exact amount that is required for the system to perform at its peak. This exact charge is so critical it is documented in the vehicle’s engine compartment down to the ounce.

A few ounces short of a full charge can result in inadequate cooling under high heat loads due to lack of reserve refrigerant. A telltale sign of this condition would be for a compressor clutch to cycle on and off faster than usual. The rapid clicking sound generated from this condition can usually be heard from inside the vehicle.

Sometimes when people try to recharge their system on their own they will actually overcharge the system which can cause poor cooling performance just as much as low Freon levels. In extreme examples an overcharge of refrigerant can even cause AC compressor damage and noisy operation.

Loss of AC efficiency

Car AC Condensor

Not as common as the Freon issue mentioned above but one that is common in my area at this time of the year is a radiator or a condenser that has been considerably clogged with bugs, dust and dirt, or road debris and trash.

When this junk starts to reduce the airflow that passes through the radiator and then through the condenser it can cause higher than normal high-pressure readings. This in turn can knock several degrees off of the output temperature in the interior cabin.

This is the kind of problem that slowly gets worse over time. It is very rare that people will take the time to check or clean the radiator and condenser. The fleet company I work for has made this operation part of the scheduled service operations. We have a pressure washer and we physically clean the radiator and condenser fins every 20,000 miles.

AC Test Guages

Although there are lots of other problems that can cause poor cooling the two mentioned above are ones that I find often. If you think your car air conditioning is not blowing cold enough the first step is to check the output temperature at the center duct with a thermometer.

Make sure the recirculation or max air mode is selected and the blower is on low speed. 40 – 50 degrees is perfect. On hot humid days here in south Florida 55 degrees is welcomed. Step 2 is to have a professional connect a manifold gauge set and get some high and low side pressure readings. With these readings a logical path of diagnosis can get your AC blowing cold as it should be.

I put together a repair modules section on my you fix cars website that talks about the theory and operation of car air conditioning. Understanding how the system works is very helpful for problem solving. You can also head back to this blog’s main page and get some more automotive repair information.

Battery powered fuel siphon

Sometimes although not often fuel quality problems can cause extremely hard-to-find engine drivability problems and repeat failures of fuel system components. Described below will be an effective way for you to check the basics of your fuels quality.

Keep in mind that you will need an accurate fuel sample from the vehicle you want to test. Although there are several safe ways to remove fuel from your tank I recommend that you pick up a special fuel siphon hose from your auto parts store. Or I have a link to the one pictured to the left at the bottom of the article.

You will also need a glass cylinder that is graduated in milliliters (also available below). In order to keep the testing simple it is best to use round numbers. Your graduated cylinder should hold 100 ml and have a cap to prevent tainted results. Don’t worry you do not have to be a scientist to conduct this test but you will need a gas sample and a graduated cylinder.

Why test fuel quality

Premium Fuels

Before I get into this short and sweet procedure for testing your fuel quality let’s talk about why it needs to be done sometimes. On a few occasions I have been faced with drivability problem that seemed impossible to solve that was eventually traced back to contaminated fuel.

I have also seen repeat failures of fuel pumps and related components due to excess alcohol content in the vehicle’s fuel supply. Too much alcohol in the fuel can do a lot of damage but one of the most common results is repeat fuel pump failures.

Many areas of the country use oxygenated fuel to help improve air quality. The additive that is used to oxygenate the fuel is most commonly alcohol. Chemicals such as ethanol have the same effect on the fuel system as alcohol.

If the alcohol concentration exceeds 10% by volume this can cause the engine to run lean. A lean running engine has higher combustion chamber temperatures and can increase wear to items such as spark plugs, valves and seats and the fuel system components such as pressure regulators and injector nozzles.

How to test for fuel quality

Fortunately you do not have to be a scientist to find out how much alcohol is in your fuel. Take a fuel sample from the test vehicle and fill your graduated cylinder to the 90 mL mark. Next you add 10 mL of water to the graduated cylinder to bring the total contents to 100 milliliters.

Now you snap the sealing cover over the end of your cylinder and shake the mixture thoroughly for about a minute. Then you can place to cylinder on a level surface and allow the solution to settle so that the different fluids separate. I usually wait an hour or two before I examine the cylinder.

GM fuel pump

Since water is heavier than gasoline the water will settle to the bottom of the cylinder along with the alcohol that is in the fuel. Water and petroleum products do not mix but alcohol and water will bond to each other and fall to the bottom of the cylinder.

If the fuel contains any alcohol the water level will be greater than its initial reading of 10 mL if the new watermark exceeds the 20 mL mark on the graduated cylinder that indicates a concentration of more than 10% alcohol. If there is more than 10% alcohol in your fuel it should be replaced along with your fuel filter. This will avoid any of the problems that can result from having too much alcohol in your fuel.

Note if you just want to test for water in fuel, you will need to get the fuel sample from the bottom of the tank. You can then just fill the cylinder to the 100ml mark and let it settle before observing the results.

The above method was taught to me by an automotive instructor in a General Motors training class. He provided us with one of the glass cylinders for us to take back to our shops. I don’t use it that often but when I do I find fuel quality problems about 25% of the time. For more information that might help you out of a jam you can return to see the latest posts on the auto repair information blog.