[335i ftw]

Has any1 had past experience with leaking coolant? Just pulled my 2011 N55 out of hibernation to see a unexpected surprise of a warning signal and topped her up yesterday to a bit over full. I woke up this morning to see the warning signal again saying coolant low and it was nearly empty. Did see little stains on my driveway but I think it's losing most of it when i'm driving. Any info is welcomed. Thanks in advance.
Ps. my fuel pump is going because it hiccups when starting or at least that's my theory.

[Nick.B]

If you can't find the leak by looking in from the top, lift it up, pull the underbody protection, and have a look from the bottom. If it's not leaking to the outside, it's leaking inside. That can be bad.

[gonick]

I just had this problem. One of the coolant hoses deteriorated from normal wear and had a small tear that eventually became huge and burst. Cheap fix if its the same problem.

[TheBingoBalls]

Originally Posted by gonick

I just had this problem. One of the coolant hoses deteriorated from normal wear and had a small tear that eventually became huge and burst. Cheap fix if its the same problem.

Same here but the hose that pretty much deteriorated and completely snapped off was located at the top, right below the engine cover. Relatively cheap fix (hose cost no more than $70) and simple repair. If you're leaking that much coolant, you should be able to find the source of it.

[gonick]

Yeah, same hose. It started off as a very small hole so I couldn't find it and just topped off the coolant every other week. Then one day it just burst and I had to get my car towed to my shop. So you should fix it now to save yourself the hassle when it does blow.

[335i ftw]

So it was the coolant expansion tank itself and I replaced that within 10 min. Apparently this is a common problem

[TheBingoBalls]

Originally Posted by 335i ftw

So it was the coolant expansion tank itself and I replaced that within 10 min. Apparently this is a common problem

The tank itself had a leak or one of the connecting hoses? In the entire E90 production cycle, I haven't read anything regarding the tank leaking - it's usually the hoses that may deteriorate over time because of the heat and rubber. I'm sure there may be a few cases but haven't read enough to deem it a common problem.

[Brown330d]

I had that sign come up recently. But I've found out its a leak in my radiator