A confusing A/C problem

The threads on a/c problems seems endless so I hope I don't bore everybody with yet another one, but my problem is becoming very frustrating and, potentially, expensive and I'd welcome any input that might help narrow down the problem.

Firstly, the car is a UK registered, 2006 Golf GT with the 2.0 litre PD engine developing 170hp. It has had the DPF filter removed and chipped accordingly and now developing something in the region of 220hp. It has been in this state for 3½ years. Six months before the re-chip/DPF work the a/c compressor was changed due to the original being seized but, significantly, the system was NOT flushed at the time.

Last summer I noticed that the a/c wasn't working - it doesn't usually get THAT hot over here in the UK!!) and it transpired that the compressor had, again, seized - some have suggested because the system wasn't flushed with the original change. However, now knowing that the flush was important I paid for a full system flush, new compressor, a new condenser and receiver/dryer and all was well again.

Three months down the line (only THREE MONTHS, note) exactly the same has occurred - except this time the compressor hadn't seized but the three plastic lugs that transfer the drive from the pulley to the spindle had broken. The supplier decided to put it down to a faulty compressor having checked the operation of the cooling fans which he suspected might be at fault.

Now, only THREE WEEKS from that replacement it seems the same has happened again. I haven't had the plastic links checked yet and it's possible THIS failure is unrelated to the previous ones but somehow, I doubt it.

Has anyone any suggestions as to what could cause this problem. When the latest failure occurred it was noticeable that immediately before the a/c stopped working completely it was putting out exceptionally cold air - noticeably colder than usual and, coincidentally, on quite a hot day (25 deg C - hot for the UK!!). The car was parked for approx 90 minutes and on a restart there was no a/c.

The shop that did the most recent work have said they have never seen failures like this and want the car for a few days to diagnose. Any pointers to help them would be appreciated.

Regards

Dave

I would first run VAG COM get some codes scanned to see what your A/C controller is telling you is wrong.

Coiuld be something simple like a High/Low pressure sensor, if you need to replace that make sure you get that from VW, I've had a lot of trouble with aftermarket units.

If you have some codes scanned, it will help all of us to help you try to diag.

Point taken. Will try to get codes read tomorrow and see what that reveals.

The code read didn't really advance things too much. It DID confirm that the compressor is still running, so that's a good sign, but otherwise there were no error codes and the refrigerant pressures didn't look great.

Off to the specialist today who will spend a couple of days next week checking it out.

Just to bring the story up-to-date, it seems the diagnostic was wrong. Whilst the compressor pulley was certainly turning, the spindle wasn't - it had seized again!!

The shop have decided that, despite the original flush done in February, the last two compressors had failed because of sludge build-up. Consequently they have done ANOTHER flush and fitted yet another new compressor (at their cost fortunately) and have monitored the car over the last couple of days.

The burning question from my viewpoint is - can I trust it. What's to prevent it seizing yet again? I guess there's nowhere to go from here?

I say check your electric fans to see if they are both still working could be putting extra stress on ur compressor also I would have the whole system checked for leaks even tho it blows cold it could still be getting low and stressing the compressor as well if nothing else replace the whole system kinda expensive I know but go all out lines grommets the works most of the time doing this will give u a good warranty for at least a year if not more sounds like you replaced the big stuff already but if they didn't replace them, the lines could have been leaking from before it could be stressing the whole new system out and sounds like it's getting bigger because the downfall seems to be progressing faster and faster to be honest I'm not sure if I would trust the shop anymore sounds like they r getting over on u even tho they have replaced warranty parts which is no cost to them other than labor I'm sure u have put in way more than the labor was worth and most shops make more in parts than labor and so far they have sold u a whole ac system minus the cheapest part (new lines and grommets) causing the problem just to charge u for more work I may be wrong but seeing as no one has mentioned leaking at all and you never said anything about leaks or lines or grommets this could be the case since u did say the pressure wasn't great

The reason they have kept the car for a couple of days is to do exactly that - check all the fans etc. We were pretty confident that they were all working before the last failure and there's every evidence now that that is still the case.

There doesn't seem to be any evidence of leaks as the refrigerant content has been OK even after the compressor failure. The diagnostic reported low pressure because although the compressor was registering rotation it was obviously the pulley that was being monitored, not the compressor spindle, so no spindle rotation, no pressure.

Apart from the the pipes and grommets the only things not so far replaced are the evaporator and expansion valve.

I can understand why the remnants of debris can cause the problem but I'm concerned that the initial flush wasn't as effective as it obviously should have been.