A/c Compressor Testing

[flames7607]

Hi everyone, glad to see forum back and running

 

My A/C does not work. Switch lights up, but no cold air. A sound from under the bonnet when the switch is on. Halfords checked it and said the compressor was knackered, but gas was OK. They want mega-bucks to replace, and will only use Eurocarparts stuff, which is poor quality. Are there any tests I can do to the compressor to confirm the whole thing is faulty (and not just the clutch) I have full Vag-com if that's any use.

 

Any suggestions gratefully received.

 

Cheers

[BrianH]

Which system do you have? MK1 or MK2? It can have pressure, but not enough pressure/charge, that could mean the pressure switch isn't being activated so it won't switch on. There is also a manual control system (with rotary dials) or a climate control system (with buttons) as well as single or dual zone. The charge required for the dual zone is higher than the single zone as well. If they have done it correctly then you should have an idea what they removed and what they put back, though given that its not working at all suggests its something besides the charge itself.

 

Depending which engine your using you may be able to get vag-com to speak to it, It would be worth a try to see if you can get any response.

[flames7607]

So it's a 2003 1.9 Zetec, with a/c button rather than climate. Halfords didn't remove anything, they checked it was gassed and did some diagnostics to see why it wasn't producing cold air, and the result was that the compressor had failed.

 

Vagcom is not showing any a/c fault, but I wouldn't know what measuring blocks to look at to see if the compressor is faulty.

 

Cheers

[BrianH]

I think from what others have said you can see if the clutch is engaging by watching it (the spindle at the end is visible, you need to see if that tries to engage.

 

If they didn't remove the gas, then they have no way of knowing how much gas is there. There may be some pressure, but that doesn't mean theres enough.

 

The mk2 has a common failure point - if you look in the top of the dryer (on the end of the condensor up at the front of the car, you can see it by removing the cover that covers the front of the radiator (you don't have to remove it completely, but the four fixings in the top are enough to get it open far enough to see) theres a cap on the end, under the plastic cap theres a metal disc held by a circlip. This allows a slow leak of gas once its corroded, If the previous charge has had the UV dye put in (which it should have had) then you may be able to see signs of leaking there. Even without the dye, if you fill the top with some water you may be able to see occasional bubbles of gas leaking.

 

If that is leaking then a regas will work, but stop working after a couple of weeks (as the pressure has dropped too low to activate the switch) I found a low charge (around 300g) was enough to activate the a/c but you'd hear the compressor clicking in and out all the time, and whilst you could feel the aircon working, it wasn't working as well as you'd expect.

 

How often are you hearing the clicking (which should be the clutch clicking on and off)?