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I've noticed a grumble whirling unhappy sound from the a/c compressor clutch on my 2008 C4S. The noise goes away when the clutch is engaged but easy to hear going down the road as the a/c cycles on and off. I did a partial disassembly this morning and see that the bearing is an NSK 35BD5222DUM18A. An internet search shows many similar bearings but not this exact one. Not surprisingly, Amazon seems to be the best source and shows it as
(hopefully that hyperlink will work). Does anybody have any insight on whether this is indeed a correct replacement bearing? I've tried the NSK website and had no luck in deciphering their part number using their online catalog. I've also searched for a replacement bearing using the DENSO compressor part number but no joy there either.
You can replace the whole magnetic clutch. Costs around 30$ here in Europe. Only issue is the wavy snap ring that seems to be specific to this AC. You might have to reuse the old one.
During install make sure you place the small washers from the middle screw in the inside, otherwise the clutch will be always engaged!
I'm still struggling to find either a replacement pulley (with integral bearing) or a replacement clutch kit. I did find the complete compressor/clutch assembly at FCP Euro, Pelican, etc with, amazingly, RockAuto having the same DENSO unit for about $200 cheaper than the main Porsche parts retailers. Also amazingly, a replacement compressor from the Porsche dealerships is about $2200.
If anyone can guide me to a clutch kit or just the pulley I would be very appreciative.
Thank you for the link. That clutch kit at $98.72 plus $66.00 for shipping totals about $165. RockAuto wants $321.79 for a new DENSO compressor and clutch. Unless I can find a much cheaper clutch kit, I'll probably just buy a compressor/clutch from RockAuto.
Today I met with the owner of an automotive air conditioning specialty shop that has been in business for decades. I asked if he could source a compressor clutch kit since I can’t find them reasonably priced from a retail source. He said that given the age of my car (2008) and the mileage (~73K), a worn out clutch bearing will soon be followed by a worn out compressor. He strongly encouraged me to replace the whole compressor.
Also, interestingly, he said that he refuses to work on Porsches because of their complexity compared to most passenger cars. I told him that I had found a reasonably priced OEM compressor and drier and could do the work myself except for recovering and recharging the refrigerant. He offered to recover the refrigerant before I started work and to recharge the system after I put it back together. He also gave me several hints about doing the job.
I will get my parts on Monday and do the project next week. I’ll post an update on how it goes.
I agree. In fact, I bought a dryer with the compressor. The shop owner told me that if I do the job on a non-humid day (we were at 32% RH today) and have the system open for only an hour or so, replacing the dryer was not necessary. But for $12.75, I'm doing the dryer too.
I also bought an o-ring kit so that I can replace the o-ring on every connection that I break.
As I reported above, I connected with the venerable owner of an automotive air conditioning shop. For $100 he recovered the R134a from my system. I then took the car home and, when the parts arrived a few days later, replaced the a/c compressor and the dryer. Both are OEM DENSO units sourced from RockAuto.
I probably spent a total of four hours removing and reinstalling the parts but I was slow and deliberate. I then went to the a/c shop this morning and they sucked down the system, held it for 45 minutes, then reloaded it with the spec amount of refrigerant. We ran the system while checking for leaks but luckily found none.
They system is cooling perfectly and the noise difference is huge. I hadn't realized it but my a/c compressor clutch bearing has been failing for a while and was making a lot of noise. With the new unit installed it is remarkably quieter in the cabin.
This was a very easy and straight forward project; definitely not one to be scared of.