So, I was sitting at the drive-thru today, picking up food. It's pretty hot. Then it started getting hotter in the car, and it felt like the air was no longer cold coming out of the vents. When I went to steer, I had to fight the steering wheel like the power steering wasn't working.
This lasted for a few minutes, and after I got my food and revved the engine while leaving, it all started working again. Steering was fine, air was cold. There wasn't any squealing like a stuck pulley or anything.

What could cause this? At first I thought I had lost a belt. But then, it all worked a few minutes later... Any ideas? This was weird.

 

You should NEVER idle your Mini for a long time (like in a fast food line). That's in the owner's manual BTW. For all its technological advancement you would think BMW could have designed a better cooling system. Also, your power steering pump fan could be compromised and not cooling the electric pump properly. Could you hear it running/cycling while you were in line? On a parallel thought, "adriancl" tuned my R53 and because I live in the Texas heat he programmed my PS fan to come on at a lower temp so that's definitely an option.

 

I had something similar happen to me, except while driving in stop and go traffic. I had my AC on blast at 60 degrees, the system shutdown for a split second then came back as soon as I got back on the gas.

I believe my issue is not enough voltage especially during short trips, the PS pump consumes so much power plus the added load from the AC and the additional power to run the blower motor. Maybe keep an eye on your voltage levels while driving, or it could be a fan issue (I replaced mine recently) since the low speed resistor had been dead.

 

I think you're probably right. I had "strange issues" when i had battery problems a few years ago. Maybe this is more of the same. Thanks.

 

How many miles are on your Mini?

I may have to replace the battery on mine, or look into a new alternator because of the power delivery issues I’ve been having.

I’ve been trying to be more mindful and avoid using the AC on short trips and just deal with the NYC heat to help reduce the load on the battery, but maybe you need it depending on your location.

 

It's got 117k miles on it, it's been around quite a bit. I replaced the battery maybe 4 years go, but it's probably only been driven maybe 4k miles since then. I'm in Missouri, so it gets pretty hot and humid during the summer. I'll check the alternator, maybe it's time to replace it.

 

I wonder if the belt was slipping? How old is your belt and tensioner?

 

I'm embarrassed to say I have actually no idea. At a minimum it's 6 years old, since that's when I purchased the car. So somewhere between 6 and 15 years old. I'll put those on the list to check. Hopefully it's not too tough to swap those out if needed. But honestly, everything has been just a bit more complicated to fix on this car than I expected.