Clean A/C compressor clutch plate & pulley

[weloveiggy]

Based on my symptoms, I decided to give this a try.
***UPDATED 7/22/11*** - Added info on removing spacers.
My symptoms were...
1) A/C worked sporatically, then not at all.
2) When it did work, it was ice cold. (I didn't suspect low freon)
3) With the connector removed from the A/C compressor, 12V positive+ voltage was applied directly to the exposed connector pin on the compressor & the clutch would not engage.
4) No strange noises. (Which might indicate a bad bearing)
5) A/C button lights up & Aux fan turns on low when A/C button is pressed.
6) No fuses blown or shorts causing fuses to blow.

I can't guarantee success, but I was surprised to find out it worked for me!
Here's a link to the originator of the idea & the inspiration for my first tutorial.
http://www.bmwe36blog.com/forum/a-c-compressor-clutch-fix-t766.html

Jack up the front of the car or use ramps. Or, like me, use both! Safety first!
Disconnect the battery.

Remove the plastic cover over the A/C belt tensioner.
http://i1199.photobucket.com/albums/aa469/weloveiggy/Compressor%20Clutch%20Fix/101.jpg

Loosen the bolt to releive tension & remove the A/C drive belt.
http://i1199.photobucket.com/albums/aa469/weloveiggy/Compressor%20Clutch%20Fix/102.jpg

Remove the clutch plate. Bentleys manual suggested using a strap wrench around the lip of the clutch plate, but I found that my Fram oil filter wrench worked just fine. Remove the 5mm hex bolt while holding the clutch plate steady.
http://i1199.photobucket.com/albums/aa469/weloveiggy/Compressor%20Clutch%20Fix/103.jpg

Remove the clutch plate.

Using a green 3M scrubby pad, clean the inside surface of the pulley.
http://i1199.photobucket.com/albums/aa469/weloveiggy/clutch1.jpg

Using the same scrubby pad, clean the inside surface of the clutch plate.
***UPDATE*** Remove spacers (if necessary) as detailed in my updated posting here... http://www.318ti.org/forum/showthread.php?p=298419#post298419
http://i1199.photobucket.com/albums/aa469/weloveiggy/Compressor%20Clutch%20Fix/107.jpg

Spray the inside surface of the pulley and the clutch plate with electrical parts cleaner while spinning the pulley. I guess, in part, you are cleaning the electromagnet inside the pulley as well. ***IMPORTANT*** DO NOT use WD40 or another penetrating oil, they are flammable. Electrical parts cleaner is non flammable & you don't want to spray an electrical component with flammable liquid. I use CRC brand "Lectra-Motive".

Once dry, reinstall the clutch plate & tighten the hex nut while holding the rim of the plate, same as in the removal.

Re-install the drive belt & using a hex bit, apply tension while tightening the bolt on the tension pulley. Do not over tension or over tighten.
http://i1199.photobucket.com/albums/aa469/weloveiggy/Compressor%20Clutch%20Fix/110.jpg

Re-install the plastic cover over the tensioner pulley & re-connect your battery.

Put the car on the ground & test.
With a little luck, it should be blowing ice cold!
Good luck & I hope you enjoyed my first tutorial!

[juan.manjarres]

Great thing I ran into your thread! My compressor had stopped engaging and took it to a shop to get checked up. They wanted to change my compressor or just the clutch. I figured I would wait it out and see what I did. I ran into this thread and did the same procedure and voila! Compressor just started working again and is cooling like she never has, Thanks!

[eurohb]

sweet jesus! imma try this since i need my car with working a/c.

[BlackBMWs]

Anyone else try this recently?

Bryan, did you do end up doing this with Tessa? How'd it go?

I have a spare, low mileage compressor and new drier/receiver, but not much time. If this make it work through the summer, I'm game to try. :cool:

[weloveiggy]

Man!
I forgot all about this!

For anyone who want to know, the a/c was still working when I sold this car two years later.

Plus, it's a super easy fix. Just see my other post that I linked to regarding removing the spacers. I really think that helped a lot too.

Good luck!:biggrin:

[BlackBMWs]

Thanks much! I have all the parts, tools and freon to replace the compressor, but it would be cool (pun) if I didn't have to.

Do you recommend cleaning the clutch surface area and removing the spacers?

I'll post results.

Appreciate the feedback, thanks again!


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[weloveiggy]

If your compressor shows signs that it kicks on and actually does cool, but then shuts off and on intermittently, then yes, I recommend giving this a try first and removing the spacers certainly helped.

Good luck!

[BlackBMWs]

Ah, currently the compressor clutch doesn't engage at all. I figure I'll try this today then if it's failed, I'll swap compressors and dryer this weekend, evacuate and reload the system.


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[BlackBMWs]

Pulled and cleaned both sides of the clutch plate and removed two spacers.

http://images.tapatalk-cdn.com/15/06/21/fbfc9a51b8eb9d4413e4f8ba309486e3.jpg
http://images.tapatalk-cdn.com/15/06/21/d2d3b9323cc42e9a1596263078355c29.jpg

Unfortunately, no difference for me. I'll swap relays to see if that matters, all fuses are intact. If still down, I'll pull the system apart and rebuild it.


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[weloveiggy]

Check to make sure you have power going to the compressor when the ac is on.

[BlackBMWs]

Thanks! I will. Also what I noticed is I have a coolant leak at the water pump. Looks like I'll take a weekend and pull the Cali apart apart to renew a bunch of items. Coolant pipes, oil filter housing gasket, all hoses, water pump, and likely A/C if power is present but no engagement. Hmmm, might be a good time to install the other thing in while the manifold is out... [emoji12]

No worries and I've collected all the required parts. Hmmm. Excepts injector o-rings. I'll order those up. No projects next weeks as I head down to watch and help out a friend who drag races.


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[BlackBMWs]

Fixed! The relay was bad. Popped in a replacement and it is working again! Yah! I'll replace the coolant pump tomorrow. :cool:

[Ivan]

Hi,
I have recently noticed that my air conditioning compressor doesnt run as before, previously, since i knew my AC clutch was quite worn out i would put fan on power setting 2 and it would run continously, i had to put it on 2 because on 1 it was engaging and disengaging wich has sense since air flow is much lower. it was all fine like that undill i turned AC few weeks ago and noticed that even if im on fan pow setting 2 my compressor is not engaged all the time. Its bothering me since i dont want excessive wear on my clutch and want to get most potential power from my AC, furthermore, if it engages and disengages while driving i can feel it taking away some power and it feels anoying. I saw this thread is quite related to my problem so i figured you may be able to tell me at least whats going on..

Thanks in advace

[bluoval6]

If it's short cycling, it may be low on refrigerant. Do you have gauges?

[Ivan]

I dont have gauges... If its necesary i could check it somwhere i guess... I can tell you that refridgerant has NEVER been filled (the car is 20yo), despite that i never really suspected on that since i didnt notice it loosing any efficiency. Why would it be short cyclying because of low refridgerant and what does that mean?

[bluoval6]

Yes, low charge will cause short cycling. What that means is the compressor is cycling out too soon and doesn't run long enough to work properly. There is a pressure switch on the low pressure side of the system that will cut power to the compressor coil at a certain setpoint, usually around 20PSI. There are 2 reasons for this-one is to protect the compressor from running when there is not enough refrigerant/oil being pulled into it, the other is to keep the evaporator from freezing up. If there has been nothing done to the system in 20 years, it's very likely low. No a/c system keeps its charge forever. Eventually, seals and o-rings get old and start to leak. If it's a small leak, you may be able to get a shop to top it off, or go to a parts store and get a can of 134a and a low side hookup. This would allow you to top it off yourself. Hope this helps.

Scott

[Ivan]

Yeah, that makes sense, thanks for explanation. I think you helped me a lot. I will update you on this case when I resolve it if you are interested.
And yeah, does it make any difference if i change out refridgerant or add how much is missing because i heard some shops are changing refridgerant?

Have a good day!

[Ivan]

Update on my case
Diagnostics showed i had 400 grams of 134a instead of 850, and 12ml of oil. System is now filled with 850 grams of refrigerant and 10ml of oil (dont know why if there was 12 but macanic said its okay, that most cars are okay with 10.) Cooling is now significantly more efficient at higher fan power settings, but still my compressor is disengaging while driving. I find that annoying and im worried about clutch wear. Since its working continously on idle and lets say 1500 rpm my guess is that compressor is ,,overpowered" for that system because all liquid refrigerant may not be able to evaporate before exting evaporator if compressor is running at higher rpm. It bothers me quite a lot because im driving on straight road for half an hour at exactly 50mph, engine about 2250 rpm in fifth gear and my compressor is disengaging every 25 sec, wich has no sense to me at all since that is relatively low rpm. It just gets worse when driving on highway...