I note that the Mini A/C is weak at best. If this IS the way it’s supposed to be, I’ll accept that. If not, what are the inherent problems using those do-it-yourself recharging systems. I assume the port to apply the charging material is that one on the left next to the oil dip stick, NOT the one on the lower right behind the radiator.
AFAIK the AC in the MINI should be able to keep up without issue, you likely have a problem. Check your cabin filter, low airflow is bad for any AC system. I am an HVAC tech, while I have no experience with automotive experience directly the theory is the same. I would not advise the repair your own systems. For one it might not be a leak(It is common on cars though) if it isn't a leak adding refrigerant will not help and can damage your compressor. If it is a leak you still don't know how much to add. If you do add refrigerant in a leaking system it will continue to leak, refrigerant does not wear out, if it is leaking the leak should be repaired. They do make the stop leak, but honestly I don't really trust it. The only time I would try the self charge/leakstop is and old car I really don't care much about. Charge it up as best you can with the kit and if it dies so be it. PS if anyone has any AC/heating issues feel free to PM me, I may not be able to do much but I may be able to help.
The AC in my '05 MCS works great! I'd suggest you get yours looked at by a professional. Without really knowing first hand what your issue is, and assuming the thing is blowing warm air, you may have a leaking component that will need replacement. I also agree that the do-it-yourself method is certainly an option, but IMHO I'd stay away from it. Good-Luck and would love to hear details of the outcome.
Also of note. If it is not leaking. Check the radiator fan for 2 speed function. Could be the cause as well. Best of luck getting your AC back
Many of the cars are under filled from the factory and do not blow very cold. have it drained and filled to the right level and it will work a lot better. over filled (the the do it your self cans) will cause it to stop work all together.
My '06 is on the weaker side, especially if you are used to AC systems from American-made cars. I do a top-up every summer on my car. Here's a how-to. How to top up AC Refrigerant in an R50/53 - Library
I only get the DIY cans that come with a gauge, for this very reason. Read the directions carefully because the target coolant pressure varies greatly with ambient temperatures. This is not one of the instances where MORE = BETTER
So far, I've been very impressed with my MCS A/C system. It's among the best of any of the 4-cyl cars I've owned. Most we've had so far is about 95F or so, high humidity; it performed well. It helps that there's not a lot of interior to cool, and I have tinted windows. Lots of good ideas for servicing, etc. Just a data point that a system in good repair should be pretty capable.
The R56 loaner I had a few years ago had an AC that rocked. It definately outperformed the R53 that was only a few years old at the time (back when it was still under warranty).
Mine was getting "tired" and weak last summer after 5 years... topped it off per Aaron's instructions and has been much better.
You need to be careful with the top off though. My A/C has always been a bit on the weak side but at one point a few years ago it became positively anemic. Took me a while to notice that it was actually alternating between blowing chilled and non-chilled air. Turned out the compressor was cutting in and out because there was a tiny bit too much refrigerant in the system. No, not my fault, I had some work done by a shop and they needed to remove the condenser so they had to empty and refill the system. I had it tested at a different shop and after a very small amount of refrigerant was removed it was back to normal. As has been said, extended operation with too much refrigerant, even just a small over fill, can permanently damage the compressor. This definitely isn't one of those situations where you want to use the old adage "more is better."
Absolutely true. Overcharged mine a bit and the compressor started whining at speed. Bled back to spec and all is well.