E90 N52 Top End Coolant Leak

[AndyG414]

Hello,

My E90 has 120xxx miles on it. I can tell my oil filter housing gasket is at the point where it could be changed. I recently noticed that my coolant level starting getting low over the past couple of days. I know for certain the coolant is not mixing with oil. It appears that the coolant may be leaking from the oil filter housing gasket (coolant hose runs through the oil filer housing.) I can see the puddle below it and the fan blew some of the coolant on to the top of the engine.

I know the oil filter housing gasket is a common failure. However, I would have expected an oil leak, not a slow coolant leak. Has anyone else had this issue or anything similar to it?

[jclausen]

Coolant could leak it's going thru the same housing, but also the oil leak will get on the upper radiator hose and the hose at the top of the cylinder head, it has two bolts that hold it in. Do replace hoses as needed when doing the oil filter housing gasket and it your expansion tank has never been replaced and it's brown in color, replace it

[AndyG414]

You have confirmed what I was suspecting. I have changed the rad hoses, exp. tank, thermostat, and water pump. I have just been putting off this gasket repair. Looks like I know what I am doing this weekend...

[bmwdirtracer]

Exactly what I would have called, jclausen.

Andrew, that ~1" diameter hose meets with a plastic endpiece....and that part has an o-ring seal,supported by plastic which disintegrates with heat. (BMW seems to never learn, about some things.)

Replace that hose, replace the OFHGasket (plus cooler gasket if that's present), and you'll be good to go.

http://www.realoem.com/bmw/enUS/show...diagId=17_0704

Damn, part 3? I don't know, the diagrams aren't very clear......

Um, best to remove oil filter before beginning. Clean all surfaces really well. Change oil when done.

There's nothing more helpful than the correct 1/4" drive Universal-jointed E-torx socket for this job. I forget if it's E10 or E12....with correct extensions,this socket saves removing the intake manifold, worth HOURS.

[AndyG414]

Thank you. I just ordered a torx bit set for this. Found a good on at https://www.ecstuning.com/b-vim-tool...t/ujet400~vim/

[bmwdirtracer]

Yeah, um, note I said "universal-jointed". This makes all the difference.