Michael Gibney

Time for a new Air Con compressor.

At page 414 of Adrian's book - at line 15 under "Diagnosis" he mentions "unless system is upgraded with heavier and more powerful compressor".

Can anyone recomend the make and model for the "more powerful compressor"?

Thanks.

Michael Gibney

springer3

I am not sure where Adrian got his information, but I think it applies only to older York-based AC systems (pre-1989 911s). The Denso unit Porsche uses in the 964 is expensive and the best available. It is a sliding-vane compressor, and very smooth. The Sanden 507 has similar capacity and is far cheaper. However, it is a piston unit and not quite as smooth. The Sanden 508 is bigger and more powerful, but I doubt it will fit.

Sandens are fine upgrades for York compressors. Densos have different hose connections, so new fittings are required. OEM is the way to go for the 964.

Michael Gibney

Thanks that information -- I now have something to put to my local auto air-conditioning mechanic when I'm looking for a new compressor, I did not even know that there were two different types of "new shape" compressors.

Additionally, I solved one problem being that my condensor fan was not operating -- simple fix -- it was the fuse, on reading up on the matter I see that turning the air con on at high speed is a known cause for blowing the fuse, I often do that when travelling at highway speeds I press the air con button to demist the ccar -- won't be doing that again.

Thanks for the info --regards -- Michael Gibney

JET951

Hi Michael , as springer3 has stated the ND compressor on the 964 is like on other Porsche cars of the same vintage very high quality ( as a side note the 911sc had the two piston york up to and including the 1983 year model). The one thing that will always be a slight concern is the simple fact that a large A/C condensor in the airflow ( behind a large grill with two electric cooling fans) is always will technically be of superior performance in very hot/ humid weather conditions as opposed to a relatively small condensor mounted behind the N/S headlight with only one condensor fan as is on the 964 and the 993 , added to this as you may have noticed that when the A/C clutch is engaged (A/C on ) the single A/C condensor cooling fan is not engaged the same amount of time the compressor clutch is engaged and net result is (when you have the A/C guages connected ) the high pressure guage does go far too high for its own good with the simple result of slightly warmer temp at the cabin air vents ( not the best result) . So make sure the condensor cooling fan works as best as it can , I will give you a clue = nearly all cars since 1994 with dedicated R134A systems always have their condensor fans engaged at the same time the compressor is running , second clue the switch unit that controls it will always come on later and later with old age as with most switches etc , or you can rewire it and add another relay so it will work like 99% of other cars on the market ( very simple stuff ) Its a good start. . Regards . BB .

springer3

Cleaning the bugs and chaff out of the condensor is a cheap way to improve cooling performance. After 16 years in the road, mine was plugged enough I could see very little light through it. It was bright and clear from corner to corner after blowing it out. It is not a fun job - get a fan and a vacuum cleaner to keep from breathing a lot of dust..