I have a facelift Omega estate 2.2 petrol 2001 and have a problem with the air con losing its coolability.
 
I have had it gassed twice recently.  First time they did a vacuum test but it passed OK.  Each time it lost its cooling after about a week.  Dye was put into the system each time and I have looked around with a UV light but can't see any leaks.  I have had the plastic trim over the condensor off and looked around there - again no dye showing.  So where next to look? 

Is it likely that the evaporator has gone in the dash board?  If so does someone know th elink to the 'how to get the dashboard off' that I have seen on the forum somewhere?

So where do I look next?  I don't want to resort to changing bits just to find it doesn't fix the problem, so any (polite) suggestions welcomed.

:-/ :question

You don't indicate if the second re-gassing was necessary. i.e. had the pressure dropped between recharges?

If you have a leak with dye in, you should find it.  Have you looked in the car behind the dash?

Otherwise: is the compressor turning when the cooling goes off?  I think the compressor works by bypassing refrigerant when cooling is not needed rather than the clutch banging in and out.  Could you have a bypass problem?

If its leaking that much the dye should be easily visible IMHO. Was it done by a "proper" air con specialist .. or a Quick Fat bunch of numpties ???

Again .. IMHO a specialist would not gas twice without finding the reason for the loss.

Thanks for the comments -

Yes the pressure had dropped after the first fill.  At the start there was about 20g of stuff in there, and was replaced up to 1900g (I think).  Second time it was down to 90g and was topped up to the correct level again.  The second time was a 'quick fix' on a friday to see what happened, with the comment that I should bring it back when (or if) it lost the coolant again.

I haven't looked behind the dash yet - again I've seen a link to how to get it out somewhere on the forum but does anyone know where it is??


I don't know for sure it has lost pressure again, but it isn't cooling so it seems likely.  With coolant in it certainly operated the clutch on the compressor OK, and now it doesn't pull in at all (but it will if you force it).  I don't know about the bypass though - how does that work?

I have no reason to believe this guy doesn't know his stuff - he's not a Quick Fat Fattie, but quotes £350 to change the condensor if it has gone - that seems bit steep for a 'simple' change with parts at approx £100 new.

Oops - got carried away there - it was filled to 950g, as per the label on the front cover, not 1900!!

check at the base of the condenser(favourite) the base of the compressor (2nd favourite).shine your uv light on the top of the gearbox bellhousing as a leak from the evaporator usually ends up there. :)

Thanks - I'll have a look tomorrow.

My pet subject at them emoment, just had a similar problem on my calibra - leak was from the compressor housing, replacement compressor needed.  The pipe to compressor joint is also a favourite for leaks.  IMHO evaporator is unlikely.

Also, the dye may not be UV so could it be you're looking for the wrong thing?  Mine was just bright green....

Dye doesnt always work, a tiny leak will lose refrigerant over time but can be too small to let the dye molecules through.
A good a/c guy should have an electronic leak tester but they are difficult to use if airflow is diluting (an already tiny) leak.

Mine as also losing gas within two weeks or so. Had a valve replaced but that was not the cause. In the end I had to replace the majorrity of the pipework. Cost me best part of £400.

I got the same with my air con, refill it and within a few hours it's all gone. Finally found the problem, it's the high pressure pipe, corroded underneath and with some tiny holes in so need to replace that pipe. All I can say is thank god There are a few garages very near by that I can take the car too to have these things checked out F.O.C

Paul :y

OK so I've had an expert look at it and he has clearly diagnosed a leak in the condensor.  He used a sniffer to check the rest of the system which seems OK.  He discharged the gas again so I can repair it (legally) and will refill the system when I have done this.

I certainly recommend Dave if you are in his area (Birmingham/Warwickshire region) - contact at http://www.aircondoctor.co.uk/.