Killers of AC compressors

Your car’s automobile conditioning system, does not just fail without some underlying reasons. Oftentimes, some salient signs would have popped up, which we may have not paid attentions to.

These days, what AC system auto shops do is to outrightly replaced a component, for instance the compressor, without actually getting to the root cause(s) of the failure in the first place.

Replacing a compressor without getting to the root cause of the initial failure, would amount to futile efforts and a waste of resources. This is because the replacement one would in no distance future, fail in the same way.


Compressors do not fail just for no reasons. Some of the reasons they fail, as follows:

  1. Excessive AC gas in the system. Too much of gas in the AC system, causes the compressor to compress more of the refrigerants. That makes the compressor overworks beyond its limit. Overworking a compressor increases operating temperatures, and hence a failed compressor unit.
  2. Low AC system gas. In order to keep your car’s compressor operating maximally, the AC gas in the system must not be lower than what is specified for its operation (safety limit). The compressor oil, and the gas, acts as cooling fluids, to help cool the compressor, and lubricates it moving parts.

3. Dirty condenser coils or fins. The main functions of fins or coils on a condenser’s unfit, is to help in cooling the fluids moving in the AC system, by dissipating heat of off the system. When the coils are blocked by debris, mud, etc, they prevent condenser from exchanging heat efficiently. At the point where heat exchange is poor, increased operating temperatures, spikes up pressures, and it’s this process, that fails the compressor.

A 2008 V8 4Runner. Left side of front view shows the condenser(with its coils/fins).

4. Suction lines that are blocked or damaged. When any of the high pressure hoses are blocked with debris or dirt’s, and/or damaged, they could lead to high temperatures and pressures, as the compressor overworks itself.

5. Not enough compressor oil and/or wrong compressor oil. Recharging a car’s AC cooling system without properly putting into considerations the volume or quantity of compressor oil, and type specified for the system, would cause a total failure of the compressor. These oils, helps to lubricate the moving parts in the compressor (pistons, etc). Only use ND8 or its equivalent for none hybrid vehicles, while ND11, or its equivalent for hybrid and electric vehicles.

Compressor oil. ND8 specified for conventional vehicles

6. Contaminants in the system. Contaminants sometimes can get access to the AC system, during a major AC overhaul, such as replacement of vital components like evaporators, suction hoses, or condenser, and also in the event of any minuscule leaks that might abound within or on the system (condenser leaks or evaporator leaks).

7. Incorrect suction line/hose diameter(size). Using suction hose or lines of a different diameter or sizes from the factory fitted parameters, would cause a compressor to fail. For instance using, a suction line of diameter of 15mm instead of the stock 20mm, would caused loss of pressure flow of refrigerant and oil, throughout the cooling system. At this point, the compressor is struggling to keep up with the load demands of the system. This generates tremendous amount of heat, that finally destroys the compressor.

One or all of some of the various causes of compressor failure explained above,could be the likely reasons for the failure of your AC system.

Next time you get to a repair shop to have your AC system fixed, do inquire from them, if they really had identified why the system failed in the first place.

A burned out Toyota Prius electric compressor

A cut through prius electric compressor, analysing why it failed. Obviously in this case, insufficient compressor oil was the cause of failure

The five cylindrical objects are the pistons that pumps the AC system refrigerant around the loop.
Any failure in the operation due to insufficient compressor oil and gas, results in a total failure.

Preventing the compressor failure.

To keep your car’s AC system, especially the compressor running perfectly well, the AC system needs to be serviced at least twice a year by a qualified technician. Some of what the technicians may likely do would be to check for insufficient refrigerants (and oils) in the system, using manifold guages, checking for leaks early in order to nipped it in the bud before it aggravates to something that would cost thousands.


that has not being taken care of.

Bookmark the permalink.


  1. This is educative! Thank you.

  2. Very good post. I am going through a few of these issues as well..

  3. Thanks for your kind words.

  4. Alright, we’d do when we require such persons pls, thanks.

Leave a Reply

Your email address will not be published. Required fields are marked *