The air conditioning system inside a typical car relies on many different components working in tandem, but two of the most important are the condenser and the compressor. You may have become frustrated recently because something appears to be amiss, but you are not sure which individual component is responsible for the issue. On average, the compressor is the first place to look, and the good news is that it will usually exhibit some warning signs before it actually fails completely.
Why the Compressor Fails
The compressor begins the entire A/C process by pressurising and then pushing the refrigerant through the system. It is designed to last a long time but is engaged in a continuous on/off cycle, so eventually it is guaranteed to falter due to wear and tear.
Bearings and Belts
You may notice a particularly loud noise whenever you switch the A/C on, and this could be associated with some internal compressor parts or with the belt that is used to drive it. Usually, potential failure will be due to internal bearings that are coming towards the end of their life and beginning to seize. This will generate a very high pitched grinding or squealing noise, which will get progressively worse until the bearing itself may seize completely. This could then cause the belt to join into the chorus as well, as the engine enthusiastically tries to activate the compressor, to no avail.
As the compressor does not turn continuously but in cycles, it will need a specialised part known as a clutch to engage and subsequently disengage it from the engine as needed. Once again, this clutch will need to be replaced from time to time, and if it begins to fail, then it will either leave the compressor permanently in the on position or disengage it altogether. Neither of these options is okay, of course, but as the clutch is an integral part of the component, it is going to be easier to replace the entire compressor.
Early Warning Signs
Usually, the first sign of trouble is higher-than-normal temperature within the passenger cabin. While it is possible to trace this back to other components, this normally signifies that the system is not able to generate enough cold air, and the compressor may not be regulating the refrigerant flow within the system.
If you are still unsure what is wrong have a word with a mechanic, who can quickly get to the bottom of the problem with your car air conditioning and return you to comfortable motoring.