Four Ways to Ruin a Car AC Compressor

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This article will appeal to those who perform their own car repairs at home as well as those who depend on an auto shop to take care of required services. Here we’ll discuss four of the most common mistakes related to auto AC that can ruin the compressor. When this part fails not only is it expensive to replace but driving around in the summer heat with no air is torture. This is also one component that if not installed correctly can cause repeat car air-conditioning problems. Educated consumers will have a better chance of achieving trouble-free operation.


AC Overcharging

AC Overcharging

When people drop the car off at the service station for needed summer maintenance they might be offered a free AC check. This means the shop connects a set of gauges and makes an attempt at determining the level of Freon in the system. They should also test the output temperature. In most cases this free service turns into an up sell sometimes called an AC service.


AC Overcharging

AC Overcharging

The proper procedure for recharging is to connect a machine to the vehicle and recover/recycle all of the Freon from the system. Then the exact amount required is reinstalled after a vacuum is pulled for about 30 minutes to remove moisture. Here is where things go wrong. You need a properly functioning AC machine to perform a high quality service. This piece of equipment can cost $4000 and not every shop has one.


AC Overcharging

AC Overcharging

Furthermore these machines need to be cared for properly and sometimes employees don’t keep up with maintenance of shop equipment. This can lead to shortcuts where they just add some Freon until the pressures look good. The problem is when they install too much. In this situation liquid Freon can make its way to the compressor. As they say in high school science class, liquids cannot be compressed. An overcharged system can destroy a compressor.


Not Enough Oil to Lubricate the Compressor

Not Enough Oil to Lubricate the Compressor

We all know that moving parts need to be lubricated. On air-conditioniners the oil is mixed in with the Freon and circulates around the system. In addition to this form of lubrication the compressor will have a sump containing several ounces of oil. Generally compressor oil level is checked only when there is evidence of major loss. A common reason to check oil level would be after an auto collision that broke a line or AC condenser. Rapid loss of Freon usually depletes the oil level. When the system is repaired this level must be restored.

This is a tricky situation because if there is a surplus of oil in the system it reduces the cooling efficiency. Too little oil results in poor lubrication of the compressor which can lead to its demise. When major components are replaced mechanics will make an effort to measure the amount of oil that was lost. In addition oil charges can be added in the same way that Freon is.


Improper Testing Procedures

Improper Testing Procedures

Automotive A/C compressors have some protection devices installed. An example of these would be the high and low pressure cutoff switches. The operation of the devices is fairly straightforward. If the pressure is too high it will stop the compressor from turning on. This can protect from the overcharge situation mentioned above. The low pressure cutoff switch stops clutch engagement if the pressure is too low.

If there is not enough Freon and oil mixtures circulating you don’t want the compressor to turn on. In an effort to test the system or see why the compressor is not engaging, inexperienced mechanics use jumper wires to bypass the high and low cutoff switches. Bypassing these safety devices can ruin the internal working parts of the once healthy unit.


Improper Replacement Procedures

Improper Replacement Procedures

Sometimes despite our best efforts we will have A/C compressor problems on our cars. If this part needs to be replaced extra care and proper procedures must be followed to avoid repeat failures. If it’s determined that an internal failure occurred, flushing becomes extremely important because this type of problem forces metal shavings into the system.

The procedure must be done with AC flush solvents that are made specifically for the task. Replacement of the receiver drier often called an accumulator on some vehicles is highly recommended along with the installation of an additional filter on the suction side of the compressor line. These filters confine foreign material to the filter and prevent them from entering the replacement unit.

If you noticed in this article all four ways to ruin a car AC compressor has to do with human intervention. Many professional mechanics live by the rule if it’s not broken then don’t fix it. This is because sometimes human error can cause a problem that wasn’t there in the first place. When there’s a problem it’s quite possible for humans to make it worse.

With that said it may be necessary to have others work on our cars or be forced to try and have a go at it ourselves. Becoming educated about the different types of compressor problems along with the procedures to repair them will increase your chances of achieving the desired results of a nice, cool passenger compartment.