AC doesn't work - pressure seems good
 

Hi,

We have a new to us 2006 MINI convertible R52. The AC isn't blowing cold air and I thought it was the compressor because of the noise we heard when the AC was on. I loaned a set of gauges and the high side pressure went up and low side went down when the AC came on. So I think the compressor is working based on the readings and the fact that I don't hear the noise outside of the car. The refrigerant was a little low according to the pressure readings for the temp so I added a little bit to bring it to spec, but still not cold. I cleaned out and replaced the cabin air filter, and frankly I think I found a rodent nest. So much crap in there and parts for acorns and stuff. Well it's all cleaned out now at least. But the AC still doesn't work right. The sound I hear sounds stronger on the driver side (left - US) and sounds like it's coming from the area behind the radio. Below is a link to a video with sound. I was wondering if that could be a bad expansion valve maybe. Anyone have any suggestions?

https://imgur.com/a/TtnDq2r

Thanks!
Billy

When you engage the AC, does the blower come on and start moving air through the vents? Also, did you try turning the AC to max / recirc / set temp all the way to the left so it displays 'Lo' on the LED screen? At that point it should be blowing max speed on recirc.

Thank you for replying.

Blower comes on and blows well. I've turned recirc on/off and can hear the actuator do its thing when pressed. Tried from Lo to Hi and all the output modes. Everything seems to work except not cold, and the noise in the video.

How long has it been since the system has been evacuated?

maybe moisture in the system? I’m guessing.

id evacuate it, install new dryer and recharge fresh...

Let us know what you find? Working to get my AC back in order. I have a leak that I can’t find so I’m afraid it could be the evaporator

Check your A/C compressor coil. It's magnetic and engages (locks up) when the system is turned on. If the coil has failed your compressor will not work properly. It's a relatively easy fix to replace just the coil but rebuilt compressors are only $100 or so on eBay.

Its your evaporator. Change that out along with the seals. Vacuum the lines and refill. It's not a difficult job. Hardest part is fitting the new evaporator on cause nothing holds it on the inside of the firewall. I used a long threaded rod and threaded it on the inside part and used a pair of vice grips to hold firm.

need to do this job. I can’t find much on it...

do you have pics by chance?

Thanks for the suggestion. What part of the issues are leading to it being the evaporator?

The evaporator is in the dash right, so I'm guessing that's fairly labor intensive. I always assumed the evaporators were a passive component so if it's not clogged or punctured it should work. And if it's clogged then does that mean the compressor may have exploded?

Since the pressures change properly on high & low side I have somewhat ruled out the compressor and its clutch being the issue. Does that make sense or could it be partially working maybe?

Thanks for the insight! I've never fixed or worked on A/C so this is a new area of fun for me.

The MINI is new to me so I'm not sure how long it's been. Potentially since 2006!

evac and recharge with new dryer seems to be the cheapest route, might as well try it! When evac'd, do I need to worry about adding more oil or should that stay in the system? I'll call around and find someone that can evac safely.

Thanks!

the oil remains. No need for more unless you replace the compressor.

keep us updated :)

If the coil is not working properly, the A/C compressor pulley will not lock up. You will be able to see that when the system is turned on. If the center of the A/C pulley is not turning (when on) the coil is your issue.

did you verify with INPA or ISTA that the ecu is seeing the right ac pressures?

AC clutch coil failure is common, pretty easy to replace it comes off the front of the compressor I do these without removing the compressor from the car just need a good snap ring pliers. I burn them up on the track, I've replaced 4 of them so far

if it were the compressor you’d not see pressure building... or is that not a safe assumption?

A bad coil is easy to solve. Start the car, turn on the A/C and look at the compressor pulley. If the coil is bad, the center of the pulley will not be turning (but the outside of the pulley will be). If both are turning you have a bad compressor.

I finally dealt with the failed AC today. I replaced the expansion valve and it's cold!! Other than it being in a hard to reach location it wasn't that bad a job as it was fairly accessible behind the gas peddle. Took at least 14 tries to install the new one before I finally got it figured out though.

I found this post very helpful. https://minicooperforums.com/forum/0...ible-r52-9544/

Also, I took a video before changing it with the plastic cover off to be more confident that the nose was coming from the expansion valve if anyone is curious.
https:/https://imgur.com/a/vtzGOPp

Finally, I bought a replacement filter/dryer but when I went to remove the current one it was twisting the plastic more than I was comfortable with. Any tricks on how to replace that? I was tired so I just left the original in.

Good to hear you got it.

The video link is broken. this one works: https://imgur.com/a/vtzGOPp

But it has no sound :(

The dryer is metal screws into the condenser assembly iirc. Several good vids on YouTube. What plastic, have a pic?

It felt like the dryer was starting to rotate around the condenser rather than turning out of it's connection if that makes any sense. Am I supposed to hold the bottom in place somehow while I turn the nut on top?

the plastic I was referring to is the mounting bracket at the top of the dryer which I probably should have removed, but that's not what I was worried about which was the bottom that I couldn't see if it was bending wrong.

Now with sound http://imgur.com/a/Kqyj9VV