Originally Posted by GOTMH8N
I've heard a bad OFH gasket can lead to smoke out of the exhaust, anything on this?
How could one check the CCV?
Oil filter housing will not cause smoke out the exhaust, just an oil leak under the oil filter housing, and on the upper hose as it enters the housing. If it is leaking onto the exhaust manifolds it can cause some under hood smoke, same with the valve cover. Any burning oil smoke out the tailpipe has to get into the exhaust first, either leaking out of the turbos (unlikely) or leaking into the motor via say the CCV (more likely).
The proper way to check the vent valve is to measure crankcase pressure. We use a device called a IMIB that electronically measures the pressure in relation to ambient air pressure. There is a spec for each car.
A little bit of oil being burned is not that unusual for a turbo car over time, as even the best turbos will allow some oil to enter the charge air pipes. How much oil/smoke are we talking?
An occasional puff of blue smoke when the motor is cold really isn't a problem to chase. This is also the case for cars pushing say, double the boost of what the car is designed to run factory (7psi). At that pressure the turbos will allow some oil past on the intake side, and this does not mean the seals are bad, its just characteristics of a turbocharger doing twice the work it was designed to. The BMW spec for oil burning on a turbo motor is a quart per thousand miles. Motors that do a lot of cold driving where the motor doesn't reach operating temp will allow oil to pass the rings more so than a warm motor, and could cause this.
Leaking fuel systems will also wash the cylinders down and cause some white blue smoke, and I'm sure as you know these motors have had a few issues with the fuel system. It all depends on how much we are talking. A video would be helpful.