Hi everyone! My girlfriend has an 03 Mini Cooper base model (I'm a BMW guy myself) and for the past week or so hasn't had A/C. I thought it was the freon, had that filled, and still no cool air coming through. We tested the compressor, found that the compressor was faulty. Replaced that, as well as the A/C serpentine belt, and still no a/c!

It seems as though the a/c clutch isn't engaging. Why could this be? Any and all help/ suggestions are welcome. Thanks!

 

There are a couple of threads describing this. Turns out that the compressors rarely go bad. It is mostly the clutch and specifically the engagement coil. Fortunately both are available. eBay for the coil and RockAuto for the clutch.

The bad news is that either can be replaced without removing the compressor and of course is much cheaper.

Of course presumably your new compressor had a new clutch? And was tested. Or was it a "recycled" part?

Rich

 

might make sure you have power going to the clutch,(check fuses,connections & relays)

 

The clutch was replaced along with the compressor.

We checked the freon level and found that it is at almost 100 psi, and looks to be overfilled. Could this be why it is not turning on? I know that other cars have a switch that will shut off the compressor/clutch when the freon levels are incorrect, but not sure about the mini.

Thanks!

 

First of all, Freon R-12 is no longer used on vehicles any more. R-134a is used on Minis.

When you replaced the compressor did you draw vacuum and held the vacuum for 30min before filling the system? You don't mention any vacuum in your posts.

If you just refilled the system without pulling vacuum then you have a soup of refrigerant, contaminants, air, moisture. If you keep running your AC system it will burn up the O rings.

Before refill you will have to fill the compressor with Pag oil. Pag46 IIRC. At least 4 oz since you are changing the compressor.

Then you need to draw vacuum and make sure the system is sealed and free of any gas.

Refill the system on the low pressure port, I think you need to put in a pound of pure R-134a. On the radiator shroud shows the capacity of the AC system.

I don't see how you would do this without AC manifold and vacuum pump though. There is no easy way out of this. You NEED vacuum pump and manifold to connect the vacuum pump to AC system.

Any question ask I will answer as I have been doing my own AC work for past 10 years on my family and friends vehicles.

 

Second question....when the compressor was off, did you remove and replace the dryier?
It function to both absorb moisture from the system and to act like a filter and get chunks of a failing compressor out of circulation....it is standard procedure to replace it anytime the ac unit has been opened up.

 

100psi is not too high for the compressor to turn on.

If there was no oil in the compressor it would have still turned on at some point until it destroyed itself, and likely then it would still be coming on but only with horrible noises.

fluid/moisture/contaminated refridgerant would still allow the compressor to turn on until the lines or expansion valve froze over. Unless someone was being a jag and put water in there or *FILLED the compressor with oil--again it would still run if only for a short period before self destructing or freezing over.


Sounds like you have an electrical issue, not a mechanical issue. Check and ensure your relay is good. Swap it with a known good relay.

Check voltage to the compressor coil, ensure that it is getting a signal voltage when the a/c is activated.

Otherwise start checking your sensors, there should be a pressure sensor mounted perhaps by the condenser or receiver drier that will deactivate the system when it detects excessively low or high pressure in the system. If this sensor is faulty or the wiring to/from it is faulty then your compressor will not activate at all.

 

might hot wire the clutch and see what happens

 

When you replace the compressor and have not added any oil, the compressor will run considerable amount before failing.

This is because no oil in compressor does NOT MEAN there is zero oil in the system.

The oil circulates through out the AC system lubricating ALL the internal aspect of the AC system and distributes itself. It just happens by design compressor holds considerable amount of oil in it. No one seemed to know even the BMW TIS, unlike other manufacturers which recommend specific amounts of oil needed when replacing different components in AC system.

If you have not drawn vacuum then the problem is simple, you don't have enough refrigerant for the system to do its job either because other gas is taking up its needed space and thus by affecting its thermodynamics and colligative properties. If this is the case you need to evacuate all gases out of the system and confirm that the system holds vacuum then properly refill.

I sure hope you didn't put water in your system as someone mentioned. WhyTF would one do that to their own or g/f's vehicle? I don't know.

If your dryer is functioning and was not in open damp air for hours at a time then I wouldn't worry too much about the dryer. Then again if the system had been open for days I would replace it. Ie if there was a leak.

To check if the clutch engages or not. Just feel your engine if you can't see the compressor directly. The increased load on the engine should be more than notable on these relatively low torque 1.6L engine without looking at clutch.

If the clutch doesn't engage that could mean multiple things. Too high of pressure in the system or bad clutch itself. If that is the case the diagnoses and the repair will change.

Who diagnosed that it was the bad AC compressor at the first place? You would be amazed how many people will recommend drastic repairs such as replacing compressors without having to have it done themselves or let alone live through it. Wonderful world of Internet! People are eager to help but they don't realize that they can harm in the process of doing it when they don't know what they are talking about.