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Have I sorted my air con after five years of trying.

Kat1

Well-known member
Joined
4 Nov 2010
Messages
178
Every year for the last five years my 993 C4 looses most of its R134a refrigerant by early summer.

Every year my local air con guy vacs out he remaining refrigerant. carries out a nitrogen pressure test and a visual test for the green dye and finds nothing.

So we refill it and try again for the same thing to happen next year.

Whilst the testing is taking place the "connectors" are being utilized. This and a hint of green dye in the connector cap lead me to try changing the connectors.

With my air con guy giving up the work (I thought £30 for a re-gas was very reasonable) it was off to Kwik Fit (£49) and their automatic machine.

0.145 of refrigerant recovered -meaning I had lost nearly 700g of the stuff in a year. Vacuum test once again showed no leaks so I fitted the new connectors and look what I found when I examined the old ones.

It will be another year until I know if I have found the problem


These are the parts that I am calling connectors



Note how the valve is offset



Valve disassembled and "legs" tweaked



"valve" reassembled and now central

 
Could be. Let us know in a year's time. Good luck.
 
I changed mine for new ones a few years back. i recall they appeared to be weeping a touch. New ones are not expensive.
pp
 
It will be interesting to see the outcome.
 
My money is on the evaporator
 
I'll put my money as well on the evap. It is difficult to spot leaks in there, but you can remove the CCU and open the resirc flap to look. The readiator inside should look clean and shiny, without any traces of oil or dirt. This is the spot to sniff with testing eqipment as well.
Cheers,
Tore
 
I dont know if you have sorted yours but hopefully Ive sorted mine following a similar period of failing A/C. Ive changed the condensor and the dryer seemed to be ok for a while then flat, I tried a re-fill after about 6 monthes and shortly after, flat! just had the evaporator and dryer changed and again flat! So my mechanic checked the alluminium A/C pipes that run along the sills and hey presto a load of corrosion around one of the rubber suspensions and the fatter of the two pipes! So ive just had the pipe replaced along with new rubbers which I picked up of the PCGB forum as a technical bulletin! A new design to combat the issue that the originals cause, can only assume some sort of friction issue. Now my A/C has never failed a vacuum test so Im thinking has the pipe been the issue all along? Our thoughts are when the system is put under vacuum the rubber suspension probably gets pulled via the hole in the pipe, tighter to the pipe, blocking the hole and then when its re-gassed it slowly leaks as the rubber will be pushed away slightly by the pressure in the sysyem. Only time will tell but if I'd know about the corrosion to the pipe issue, I'd have saved a s**t load of money. So Id suggest checking the pipe work in the sills before moving to an expensive evaporator replacement!
 
Mike-M said:
I dont know if you have sorted yours but hopefully Ive sorted mine following a similar period of failing A/C. Ive changed the condensor and the dryer seemed to be ok for a while then flat, I tried a re-fill after about 6 monthes and shortly after, flat! just had the evaporator and dryer changed and again flat! So my mechanic checked the alluminium A/C pipes that run along the sills and hey presto a load of corrosion around one of the rubber suspensions and the fatter of the two pipes! So ive just had the pipe replaced along with new rubbers which I picked up of the PCGB forum as a technical bulletin! A new design to combat the issue that the originals cause, can only assume some sort of friction issue. Now my A/C has never failed a vacuum test so Im thinking has the pipe been the issue all along? Our thoughts are when the system is put under vacuum the rubber suspension probably gets pulled via the hole in the pipe, tighter to the pipe, blocking the hole and then when its re-gassed it slowly leaks as the rubber will be pushed away slightly by the pressure in the sysyem. Only time will tell but if I'd know about the corrosion to the pipe issue, I'd have saved a s**t load of money. So Id suggest checking the pipe work in the sills before moving to an expensive evaporator replacement!

It was me who posted on PCGB forum, however credit should go to Endoman who posted the TB up here first..........911uk.com - if Carslberg did a Porsche Forum :thumbs:
 
I just sorted mine with a new A/C control unit. Also fixed the battery drain issues. Not cheap.
 
The sill pipes expand and contract longitudinally, long pipes and aluminium, so probably quite a lot. When the a/c is running one is icy cold the other too hot to touch. If there is any corrosion around those mounts the constant movement and friction from aluminium oxide will wear them through. My sill had also rotted in that area. Easy enough to check by removing the r/h sill cover (rocker panel), but not if you have RS ones, they are a real pia.
 
Gentlemen many thanks for the input.

Am I correct in assuming that those of you who suspect the evaporator is faulty are basing this on personal experience of similar problems.

I will be implementing the recommendation to check the evaporator visually with the CCU removed and will also be checking the sill pipes this week.

It is about nine years since I replaced the evaporator (pattern part) - Is the foam used to "seal" it any thing special ? IE does it have to be resistant to something etc or are there any part numbers/ places to obtain it.

Also I note that I can get an OE evaporator for circa £500 and a pattern part for about 40% of that.

Has any one any views on which one to fit? If so why?
 
Pipe along sill have been checked. Unable to remove the rubber mountings without disconnecting the lines.

My pipes have a rubber sleeve where they go through the mount - pulled this back to reveal some light surface white dust - no sign of oil or refrigerant.

I will check out the price of these pipes and make a decision as if I change them next time the system gets a re-gas.

Time to take the CCU out and see if I can see the evaporator.







 
Just ordered the large dia one from Glasgow Porsche - £154.00 ish.

Doing the job next week, just in time for the end of summer :wack:
 
Dont bother looking in the right hand sill area, nothing to see there :eek:
 
As you've had an evaporator I'd say you are Ok in this area :dont know: as some are still going 15+yrs but as we know they wont last forever.

Try the visual check and rule out everything else first as it is a PIA labour wise. An experienced AC teccy should be able to trace the leak with the dye and sniffer. IIRC Hella evap part is c£220

I'm going for a pattern part on mine (last one I got for the 993 was fine) as once its sorted the AC will never be switched off to ensure it stays efficient. Lack of use kills them off
 

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