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Air conditioning

The air conditioning only cools when I am driving. It usually doesn’t cool at idle.

This is annoying when you come to a stop light.The shop mechanic said the relief valve in the compressor was bad and letting freon escape.The only way to repair it is to replace the compressor.

I suggest taking your car to a local (not a chain) A/C shop.  Often they are radiator and A/C shops.

Get the second opinion.  I can think of one or two other possibilities, but it is difficult to tell from here.

It may be helpful to tell us what year PT Cruiser you have.

I have a 2003 PT. I welcome your two other possibilities.

Well, I believe one of them may be that your cooling fan is not coming on. That will keep your AC from cooling properly due to excessive heat. See if the fan operates at idle when your AC is turned on. It should if it’s working properly.

Does the engine have to be at normal operating temperature, or will the fan come on when the air is turned on if engine is cold?

I believe the fan comes on as soon as the AC is turned on on most vehicles regardless of the temperature. If your fan is not coming on then warm up the engine before turning on the AC to make sure.

The fan did not come on after starting the cold engine and the air on. I let it idle with the air on and the engine reached normal operating temp, still no fan. The compressor is cycling very fast every 4 seconds on and off. There was one occasion recently where I made a trip to the store, my wife went in and while I was waiting I noticed the temp gauge went hot.This is not normal for this car which also points to the fan, I normally notice when it cycles.You may be on to something. Where do we go from here?

What are my options. Is there a fan relay? if so is it easy to check?

You need a good mechanic to check this out. It could be the fan relay, the fan motor or even a broken wire. You need someone with troubleshooting experience or you will be throwing parts at the problem without resolving the actual defect. Hopefully it’s a simple repair.

Thank -You

If you wish,find and exploded view of the compressor and have the mechanic point out just what part on the compressor is acting up. In the 80’s some driers had plugs in them that would get pushed out either from pressure or temperature but a relief valve internal to the compressor,I am not finding one.

Now if this is a variable displacement compresor perhaps the valving that sets the displacement is acting up

I have no idea what Chrysler anything is like, but I know that on a-lot of GM automobiles the fan relay will be identical to another one beside it. Same part #. If it’s like that you can swap the relays to see if that is the problem.

That would really be bad for the mechanic,to give a diagnosis of an internal compressor fault when all the problem is, is a fried relay.