IAA-C63

I was driving my C63 (about 3k miles on it) home from today from work, and after about 5 minutes, I decided to have some fun. I put it in M3 at about 4k to 6k RPMs, and after about 3 minutes the car switched to C mode (while I was in a curve!). I put it back in M, but it went back C after about 30 seconds. Same thing happened a couple more times, so I left it in C for a few minutes. I then went back to M and it stayed in M. When I parked at home, I heard a loud fan noise (like a vacuum cleaner) coming from the engine area, which stopped after about minute, and which I've never heard before.

What's going on? Is this normal? Something wrong with the transmission? Overheated transmission? I've heard about limp mode in other threads, but I wasn't pushing the car that hard, nor for very long. I do probably need to add engine oil, since my "check engine oil" light has come on a few times in the past couple of days (but it doesn't always come on, so the oil seems to be only a bit low), but I'm guessing that doesn't have much to do with the transmission anyway?

Of course, I can take it to the dealer and get it checked out, but I don't want to waste time with that if this is somehow normal. Plus there are no warning lights on.

SMP

When the transmission reaches a certain temperature in M mode, it defaults back to C mode in order to protect it from being cooked. If you cost for a little while in C the temperature will come down to a safe level and M can be selected again. If ambient temperatures are high combined with some spirited driving without letting the car cool down before parking it, the fan will come on while parked to dissipate heat from the engine compartment.

BerBer63

What was your oil temp? I think the magic number is 265+F

IAA-C63

I checked that and it just showed some dashed lines. I'm thinking that means the oil temp was still relatively low?

IAA-C63

That's what I thought, but I wasn't pushing the car that hard for that long (ambient temp was about 84 F). By comparison, I drove the car much harder and for much longer in M a few days ago, with ambient temp over 90 F, and it stayed in M.

IAA-C63

Any chance that holding high RPMs for a while heats up the transmission too?

alrasheed1991

just add oil i had 60% of your problem car was new and the check engine oil light on and i was pushing it hard until some guys at traffic light say to me some smoke is getting out of your front right side of your car so pulled over called dealer and they say just add more oil
good luck hope i helped

rst63

You have to actual start up the car with the engine running to check the temp. no just turn the starter to the accessory position.

Even Money

Nope...Just turn the key to the second position.

IAA-C63

The car was running and moving, and I actually checked it while I was having the problem.

IAA-C63

My "check engine oil" light still isn't coming on consistently, but you may be right that needing oil may be part (or all) of the problem. I was hoping to take care of that yesterday, but was swamped all day at work. I can hopefully do that Monday, and will take it easy with the car until then.

I'm still puzzled though about why none of the three temp gauges showed anything to be too hot. I'm not aware of there being a temp gauge for the transmission. Does anyone know if there's a transmission temp warning, other than the car going into limp mode?