Baby BMW Forum banner
1 - 3 of 3 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Hello and thanks for reading, I know N series engine Valve Cover Gasket (VCG) leaks have been discussed in every corner of the internet so only posting because we are really stumped... I was parking at work one day and a wave of whitish smoke rolled out from under the hood - tbh noticed it first at front left corner as viewed from RHD drivers seat, and accompanied by burning smell. It passed quickly enough that couldn't see where on opening hood but smelled like it came from area behind engine and firewall near steering column (RHD car).

Pulled vanity cover off and the foam block out, and noticed two things; dark trace of burnt oil running down oxygen sensor onto cat at the back, oil film on exhaust manifold flange around cylinders 5/6 and oil pooling between cylinders 1 & 2 at the front. Figured bound to be VCG since car is 10 yrs old and 95,000 kms. So I replaced the VCG with gaskets (outer + 3 inner) bought from local BMW specialist. Dry fitted them, checked seating with inspection cam etc. and torqued in 3 stages to spec. Went over cover very carefully and no signs of cracks anywhere. Wasn't even particularly warped when we checked for run out on a flat surface.

Well, for a week no issues then again, parking car facing uphill at work the same old roll of smoke. Pretty sure I fitted it correctly first time but just to be sure, pulled it all off and this time used smalll bead of Ultra Black behind the gaskets to hold it in the covers, and a very light smear on the face of the gaskets. Cleaned mating surface on block and refitted. Torquing etc. And each time had removed all the braces, plastic housings etc. at back of engine bay to ensure good access for the torque wrench when working with the rearmost bolts.

For another week no issues then again (!), parking car facing uphill at work the same old roll of smoke. Wtf?! So this time put it up on my hoist and pulled under trays off. There was some residual oil running along bottom edge of exhaust manifold flange that I couldn't get to from above and didn't clean off first time (see below) but no obvious leak that would drip. Parked car up with front wheels on ramp and ran it for an hour and no smoke. So it needs to be really steep hill (like my workplace carpark) to recreate this phenomenon.

Bumper Rim Gas Automotive tire Auto part


Cleaned all this up so it is spotless around that area and drove it around. And sure enough after a few more days, same old roll of smoke.

Put the inspection cam in the area and it still looks pristine as per shot of the lower exhaust manifold studs on Cyl 5/6 below

Automotive fuel system Motor vehicle Automotive exhaust Gas Auto part


So if it isn't VCG leaking oil over the cats (my assumption), what on earth could this be that is triggered periodically by a steep uphill incline? The turbo oil feed/return lines are not leaking. Did the oil filter housing etc. last year and all good. If it is possibly coolant and not in fact oil burning then from where? Is the fact that the smoke seems to emanate initially from the front left relevant? Fwiw, the expansion tank show no sign of leaks/cracks (plus it on the opp side).

Has anyone else had this? All ideas welcomed... thank you.
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #3 ·
we couldn't find any cracks or 'sweating' after refitting and torqueing down (but not ruling anything out). There is a really small leak from the turbo oil feed pipe off side of the block but such a pain to swap that probably leave that to a bit later when I do the oil pan gasket at same time. Interim, cleaned it all really throroughly, and touch wood, the issue seems to have gone away. If it returns over time hopefully we will be able to see where from.
 
1 - 3 of 3 Posts
Top