please help with ac issues

Repoman · #1 08-18-2009, 09:10 PM

I recently joined as a member here and this is my first post. I have found this sight very helpful on previous problems I've had but this one is stumping me. I have read dozens of posts on ac issues with the x5 and some are similar to my issue but nothing exactly like mine. I'm not a big fan of just replacing parts up until it starts working again, especially at the prices of these parts. My wallet and I would rather replace only the part that is faulty. Well, here goes.

My ac is blowing outside air temperature air only when any ac function is selected on the ac control panel. My condensor fan up front never engages. My ac compressor never engages. I do get the kickdown from the engine when the ac button is pressed but no compressor. It will always blow exterior ambient air temperature air no matter what speed I am driving, and for however long I have been driving. I would think that even if the condensor fan is not working, driving at a higher speed would simulate it working and allow the compressor to do its thing. However, even during cool nighttime cruises at higher speeds for longer periods produce no cold air. All other ac functions seem to work properly (all interior vents seem to be working fine and all blower fan functions seem to be working), just no cold air. My fuses are all fine. AC system was checked for freon and it was full, would not take a charge.

My thoughts were that it is probably the condensor fan but if that was the case, wouldn't I get some cold air on one of those cooler nighttime high speed cruises? Also possibly the FSR but all other functions that the FSR controls are working just as they are supposed to. Could be the compressor since it never comes on but at 55K miles . . . it better not be!

It was working great one day when I got out of it and 30 minutes later when I got back into it, no cold air. Has been a week now with no cold air. I've tried to be as detailed as possible but if I've left something out, let me know. Can you good people assist me in my diagnosis? I have read pretty much every post on here for ac issues and nothing seems to be exactly like my issue. Thank you in advance!

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Weasel · #2 08-18-2009, 10:29 PM

Well, if the fan speeds are all working properly it isn't the FSR. If the compressor isn't engaging, that is why it isn't cooling... the question is why isn't it engaging. It won't engage with no pressure, but going from all to none in 30 minutes would take a very noticeable hole in the system with the pressure hissing out at you, so that isn't likely the case.

You could always take a voltmeter and check for power to the single wire to the compressor when the ac is "turned on". If the 12 volt signal is there and the compressor doesn't engage then you have a bad clutch. If there is no power there, something is stopping the DME from releasing the compressor. (the IHKA makes the request, the DME analyzes the inputs and releases the signal to the compressor) In this case, you could try jumping power to the compressor with a fused wire to see if it activates and blows as cold as normal. (I say fused wire to prevent melting wires if there is a short)

And I say all this hoping you checked fuses first.

Repoman · #3 08-19-2009, 01:09 AM

Thanks Weasel! I was hoping you would chime in because all of your posts are not only very informative but also easy for me to understand.

I will perform this test tomorrow in the daylight. Hopefully I learn more about the problem tomorrow but if not I will report back my results and hope for further diagnostic advice from you. It gets real hot here in Houston in August.

Repoman · #4 09-05-2009, 04:33 PM

Ok I checked voltage on the single wire going to the compressor and it does have 13.55 volts going through it to the compressor but still no compressor engaging. I did spin the compressor shaft by hand and it does spin freely, just won't engage. According to your post, it must be the compressor clutch right?

Also, does the compressor need to be spinning in order for the condensor fan to engage? because my condensor fan does not run at all.

Is there anything else I can test to clear up the diagnosis a little more?

Thanks in advance! It's in the mid 90's today.

Weasel · #5 09-05-2009, 07:51 PM

The condenser fan is controlled by the DME, and its activation depends on inputs from a number of sensors in the engine and air conditioning system. I wouldn't worry about the fan too much at this point. But if the single wire to the compressor was getting battery voltage when ac system is activated and the clutch isn't engaging, the clutch is the problem. BMW doesn't sell the clutch separately from the compressor, but I remember a member or two having their clutches repaired with individual parts from a specialty shop or something. Definitely worth a search as I seem to remember them having success.

Repoman · #6 09-10-2009, 07:46 PM

I did the search on here just like you suggested (Weasel) and found some great info about compressor clutch repair/replacement. Katit (member) had a great write up with pics that showed how he removed his clutch and replaced it with an aftermarket one. Following his directions, I removed the clutch from the compressor, didn't even have to crack open the system. I called Adam at All For Auto and ordered the replacement clutch. Katit was right about that Adam guy, his customer service is off the charts. This is going to save me between $500 and $1400 on this repair since BMW only sells the compressor w/clutch and not the clutch seperately and of course you must crack open the system to replace the compressor. Katit posted that his worked like a charm so I am expecting the same result. I'll repost with results after repair is complete.

Weasel · #7 09-10-2009, 08:02 PM

Repoman · #8 09-17-2009, 12:38 AM

Well I got the new compressor clutch in the mail. After several attempts to reassemble, the snap ring that holds the compressor clutch to the compressor got the best of me. Not near enough room to work in there and also working blind. I unbolted the compressor from the block to allow me some more room to work but still no go. I had no choice but to crack open the system and remove the compressor completely so I could reassemble it. Reassembly at that point was a breeze. I now have the compressor back in and lines are reattached (hand tight). When I had the compressor out I drained as much oil out of the compressor as I could so I would know how much I put in. I have a few questions regarding recharging the system.

Questions:
1. How much oil do I use to refill the compressor?
2. What kind of oil do I use to refill the compressor?
3. Any ideas on the best place to rent/get one of those vacuum pumps?
4. Does anything else have to be done?

This is all I need to do to get back on the road again.

Weasel · #9 09-17-2009, 01:10 AM

1. same amount as you drained.
2. PAG oil.
3. Not sure...
4. Just make sure you have it on vacuum for at least 30 minutes, and get it charged to the proper amount as it is easy to overfill a system that only takes .98 lbs of refrigerant.

Repoman · #10 09-17-2009, 01:25 AM

Thanks again Weasel. One problem I have is that I wasn't able to measure exactly how much oil came out because some spilled out during removal and some more during reassembly of the compressor clutch. I figured the safe thing to do would be to drain it all out so I knew that how much I put in is how much is in there.

I did some searching on the internet and found what you suggested also . . . does PAG100 sound right, also found PAO68 but no quantities listed. I did find a few that said look at sticker on compressor or under hood for quantity. I hope I have one under the hood because I know there is not one on the compressor.

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