Air Con Not Working.

Hi, 2005 4.4 V8 Petrol .
I have had the mechanic change the compressor for a new one, (twice because we believed the replacement was faulty). It has been re-gassed and holds a vacuum, so no leaks. Apparently when the pump cuts in it starts to pressurize and then stops. Pressure sensor was changed but still doing the same thing. Has anybody come across this before?

Over dosing of oil,
Blocked jammed expansion valve,
Blocked evaporator in dash,
Debris in front of the condenser rad,
Main engine fan not working in accordance to the aircon
The readings on the gauges for the aircon machine should give some indication of where to start looking

is it losing the pressure it does build up?

I still don't see the logic of using a vacuum to test a pressurised system. Shirley a vacuum has the potential to suck joints together that would push apart under pressure?

backinblack said:

is it losing the pressure it does build up?

I still don't see the logic of using a vacuum to test a pressurised system. Shirley a vacuum has the potential to suck joints together that would push apart under pressure?

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Agreed. It's a good indicator, but cannot beat a nitrogen pressure check.

I've used compressed air in the past which made finding condenser leak easy, but that required extended vacuum pull to clear the system afterwards.

Currently my compressor has a leak around the shaft where the clutch attaches. Only found it after a re-gas, and later checking why the clutch was noisy !! Replacement compressor (with staff discount) waiting for me in Bedford Euros.

You will be better off using a specialist vehicle A/C firm than your local mechanic when it comes to fixing A/C problems.

nigelbb said:

You will be better off using a specialist vehicle A/C firm than your local mechanic when it comes to fixing A/C problems.

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Even better to DIY