R53 A/C Problem (detailed)
 

Yes, I've searched. Yes, I've read all the threads....

2003 R53, A/C blowing hot air.

- checked all fuses
- checked all relays
- a/c light stays on solid, not blinking

Took out radiator fan, it had the bad resistor so we swapped the whole fan unit out.

No matter WHAT we do, I cannot get the a/c compressor clutch to engage. Jumped out the low pressure switch. Jumped across the a/c compressor relay. Tried bringing power straight from 12v to the a/c compressor.... all no dice.

What do I do next? Is the compressor shot?

edit: Checked the refrigerant pressure, but since the compressor won't run, I suspect the reading is bogus.

It has been well documented that the clutches on those compressors go bad. It happened to me and I could not source a clutch without the compressor. I do remember at least one thread where someone found a clutch but it may have been off a junker.

I think you'll find a new compressor fixes your problem. Assuming all the other things you checked and were fine, actually are. It is a common problem BTW.

Rich

This

How does one check refrigerant pressure? My 05MCS blows cold, but not A/C cold.... I have a feeling im out of charge.

I have a gauge (like $10 at the parts store) that checks it, but it'll only work if your compressor is working.

(so -- since my compressor won't turn on, the gauge isn't accurate. oh, and also since the compressor won't turn on, i can't even attempt to add any refrigerant to my car)

You can still test the static pressure if the ac compressor is not operating, engine running or not. Most systems have a low pressure switch which looks for ~50psi to activate and engage the compressor. It depends on air temp. But at say 50psi static pressure, if your clutch works, your compressor will cycle on and off as the suction side pressure decreases. It will switch off the compressor at about 20psi, the pressures will start to equalize and your compressor will turn on again and continue this cycle.
If you have no or low pressure, add refridgerant with the engine running, ac on full, windows open.

Tried to, but it seemed like without the compressor going, system would take no refrigerant....

Do you have a gauge connected?
What is the pressure?
When you connected the hose to fill it up / check pressure did gas escape?
If you depress the schrader valve where you connect the hose does gas escape?
It should hiss a lot, not really recommended but a quick and dirty check.

Even with the engine / compressor not running, if you have gas in the can you should be able to charge the system, as long as the pressure in the system is not higher than the can. That would not be good.
Only fill system with engine running and ac on.

My compressor went bad at around 70k miles and then 2 days later someone hits me in the front and damages the AC compressor, FREE FIX!

I do not suggest you go out and get hit, just saying I got lucky :)

Compressor was dead. You don't want to know what the dealer charged for the repair....

Sadly I do, as I might be facing that. I did find a site that sells the parts in a repair kit for $425

A kit for the compressor or a new clutch? My experience is that the compressors are good but the clutches are going south with no source for a new one without a compressor attached.

If the compressor was bad, the clutch would still engage but the pressures would be low or non existent.

In my mind buying a rebuild kit with no way to test it on the bench is risking the price of the kit and the time to take it apart, put it together and take it apart again.

Rich

A/C clutch coils go bad. Check it out. I have two how-to videos.

http://youtu.be/y9DQasHwdQA

You can check continuity to clutch by going from relay output to clutch coil and seeing if you get any ohms. Open means its shot. Good news is that is comparatively easy and cheap. A guy on Ebay sells just the coil.

Nice video Dirkdaddy!!
I am looking at doing the same 'project', a couple of questions.
Which wire is it or pin is it on the relay connector that you check continuity on?
Is the bolt difficult to undo on the end of the pulley, it looks like a hex?

Bolt question first - its not on that tight, I used a long pry bar stuck into the outer clutch under something protruding - be a bit careful but its not fragile. I braced this under the car on the floor to hold the thing from spinning, or use a helper.

You can go to the mini's relay bank underhood, find the one for the A/C. Remove the relay, look at the wiring diagram on the relay. If you have not dealt with one of these they are simple. Basically you have a low-current circuit that has a small electromagnet. When you power that it energizes and throws a bigger switch. The pin thats not connected to anything on the diagram but near the switch swinging door for lack of better terms will be the output, but you can check with meter. With Key on the relay should have power to the other side of the relayed circuit.

On the socket for the relay, one will be ground. One will be the 12v from the AC switch on the dash, you'll need key on and switch on. Test voltage using multi-meter and stick probe into socket. confirm that its the one by using the dash ac switch on/off. the other hot socket hole will be for the 12v feed that the relay switches going to the a/c clutch. there will be two "outputs" typically, one of which is wired to the A/c clutch, and after it goes through the electromagnet in the clutch goes to ground. If you look at the relay diagram it will make sense.

What happened to mine was that the clutch coil went "open" or no longer was a circuit and did not flow any power, so it did not energize. You can test for this condition by using the multi-meter on "ohm" setting and using the relay socket going to the clutch. You can try a mid-level ohm setting just to be sure instead of the lowest where I normally do continuity testing.

To remove the coil you will need to unbolt the compressor - leave lines attached! You will need a GOOD circlip tool with some deep nose on it. I used a cheepy one but it was a bit tough, does work. After struggling to remove the compressor and complaining about it a guy told me to unbolt the lower engine mount and use a load strap to pull the engine rearward to give additional space. Without that is very tough, I know!

The part is hard to find but I managed to find one on ebay of all places new in box. was only about 120$ and fixed the car!

Good luck let me know if you need clarification.

Nice, I will look up what contacts to check later.
I have seen the clutches on ebay, it makes life so much easier and cheaper than changing the complete unit. I wanted to find someone how had done it first. (-:
We bought the car with non-op ac, I was expecting it was the clutch, I just need to verify first it is not something else. The gas is still charged and the fuses looked intact.
By changing the clutch the compressor could still be faulty but you have to start somewhere..

Hard to find the clutch w/o compressor which can run $800+, but the main clutch related issue seems to be the clutch COIL which all I had to replace. You can inspect the flat mating surfaces but in many cases they will be OK. Some cars have a thin layer of friction material, cant honestly remember on this one. Also, use the original "spacer washer" between the shaft and the outer hub when you bolt that on to provide proper spacing.

Hi Dirkdaddy, is there any part number or reference for that coil? I'm trying to find one but can't find any on ebay ou else were... :sad:

I'm searching by "BMW MINI Clutch Coil" "Delphi Clutch Coil" and other things like than and no luck!

Too many words. Try" mini clutch coil " they are there.

Found it!!!! :thumbsup: :wink:

http://www.ebay.co.uk/itm/3307360034...84.m1438.l2661

http://i.ebayimg.com/00/s/MTIwMFgxNj...7E%7E60_12.JPG

I am working on getting the pulley off right now, and the bolt is really stuck on there. I am just curious if this is a regular right handed thread or a special left handed?

Thanks

Regular right handed thread. :wink:

I finally got the bolt loose, thanks Dirkdaddy and MNPF.
My bolt was very tight and got messed up loosing it. I then welded an old torx bit I had, to the bolt. The torx just broke. I then welded a hex bolt after I grinded down the mess a bit. It finally came loose and was tight all the off. It looks like there was thread locker on the bolt or maybe it was just the salt from New England weather..
New clutch now installed and ac nows works, when we bought the car the ac was non-op so very happy with this fix.
Also installed a new belt using a tool from ebay, worked well.

Those bolts really need an impact gun to make them a non-event.

Just to to help anybody looking for part numbers of this clutch kit:

http://album.mnpf.net/online/30052012527.jpg