N54 Coolant Issue Help (135i)

[cdog_6643]

Hey, I just ran into an issue with my coolant system on my N54 135i and need help diagnosing what the problem is. So to describe what has happed so far is as follows; Driving on highway for 40 minutes then coolant light went on and went into limp mode, pulled over and saw it had busted somewhere, checked all lines and saw nothing broke, let car cool down and it started right up after sitting for about 10 minutes, needed to get home so I pushed through and car kept running smooth until the same problem occurred but no spillage. I let it sit over night and checked coolant levels and refilled what was lost.

The next day after checking levels, I watched my coolant temperatures range from 172-210 degrees F running fine and after about 30 minutes (of light driving) it'll shoot up to 240 degrees F plus along with throwing the coolant light up. I'm quite confused since the car runs fine even after letting the coolant cool down and no lines seem to be broken. I took a look once the coolant dried up to see where it splashes from and it seems to be busting out the seems of the coolant housing. I would feel for any spacing between the housing and it got gradually bigger where it seems to be spilling out of (seen in one of my attached pictures). Is it in need of just a new coolant housing or is it something more making the car overheat and the coolant to expand out?

I appreciate the read through and hope to find an answer soon as I need the car up and running to go to work!

[GoRomeo]

Dude from the photo that looks like your coolant expansion reservoir needs to ne replaced. Its busted. See around the sides. Same thing happened to me a few days later I bought my E88. I had to replace it along with a new cap to be safe. Its easy to replace. Make sure you follow the bleeding process.