i have 1998 e39 with 160k milage,my oil consumption is very high : 600miles 1 liter.

i search and found some threads about bad ccv and i did this test:
i opened oil cap and cover there with plastic bag while engine is running its slowly sucks in.

So is there any probability that ccv is bad and pass this test?

my symptoms are:
burning oil
rough idle
oil smell like gasoline(very much)
no blue smoke from tailpipe
heavy white smoke from oil cap when i open it while engine is hot.

Please Help...

Have a crankcase pressure check done. If the CCV is operating normally the pressure will be 3-4" of water. A greater vacuum would indicate a failure of the CCV.

i will do crankcase pressure check but i cant do it these days, when i cover my hand to oil filler cap i really feel vacuum. Is it normal for 3-4'' pressure?

Just got back from the shop this morning, crankcase pressure check showed 5.5" of water - still worth replacing the CCV? I read a technical bulletin that stated 3-6" is within the normal operating range, and the tech at the shop tested another BMW that showed around 5". He thinks they like to be in the high end of the 3-6" range.

Mine too,i think we had no problem with CCV..Thank you

I changed my CCV as a preventative measure since winter is coming up and I've heard stories about the rubber diaphragm in the valve having a tendency to freeze and fail.

Crankcase pressure with my old CCV was close to 6" of water (5.5-5.7 in), after replacing the CCV crankcase pressure went down to about 4". Time will tell if the burning oil issues resolve themselves from this fix.