I need to replace my AC Compressor on my base Countryman (N-16 engine) and Rock Auto has them with 2 different sized pulleys (4.28 and 4.68). Without getting under the car and measuring does anyone know which pulley size is correct for my car and/or if it really doesn't matter which size i get?

 

Well, the smaller pully will drive the compressor faster… I think you’ll just have to make sure you get the correct length belt to drive it….

 

Hope someone knows this information. I have the same N16 and would be interested to know what size pulley you have (big or small). I recently replaced the drive belt and there seemed to be one size only so perhaps this can accommodate the 0.400" diameter differences?

 

Here's what I'm seeing on Rock Auto's site: https://www.rockauto.com/en/catalog/...nent+kit,17507

 

Ya that sucks it is so hard to find the right information. I looked on Autozone as well and it seems to call out the smaller one there if there was any pully diameter information to be had. You might need to check on RealOEM as it seems perhaps you need to know the month yours was produced.

Just going off of their options I saw on RealOEM, they list the compressors with the belt numbers (X905 or X895). After April of 2010, there was a change it seems. It lists the compressor and belt where the belt appears to be the shorter (part number X895) than the other (X905). So I would assume this potentially correct one would be the smaller pully with the X895 belt as listed:

 

damn. It may not be the compressor or clutch after all. My cooling fan isn't operating either and I've read that the cooling fan relay being inoperative wont allow the AC to kick in. What a PITA to diagnose.....

 

Maybe it is a bad relay or relay connection. I've had some issues with those in the main fuse panel. Push on them and swap them around maybe. I had an intermittent relay issue causing all sorts of problems with the DME. I swapped relays with the cooling one and it went away. Replaced the relay and that problem didn't come back.

 

I replaced the refrigerant pressure switch and the radiator fan relay, recharged the AC system and now everything is back in working order.

 

That's great you were able to not have to replace the compressor and found the issue. I assume it was preventing the compressor from starting in the first place.

 

Best bet is to look at old belt and see the marks for the length, on the outside of the belt they are printed with the Size and it will have 6 or 6PK and then the size or a part is aftermarket that crosses to the size. Even when worn you can see it from the top of the engine or under side. X905 or X895 that's the length in MM. Dayco Italy is the OEM for the Gen 2 MINIs BTW.

 

That's how i understood the system to work. The cooling fan needed to see pressure from the AC system before it would activate the cooling fan. In any event, replacing those two parts and recharging seemed to be a good fix.