extreme coking of oil on e-46 head

hushpuppy · 02-10-2013, 04:11 AM

Has anyone seen extreme build up of dry oil sludge (at least 1/4th to 3/8 inch all over the cam assembly) on their cam assembly in an e-46 head. what causes this. THE CAR HAS ALWAYS HAD DEALER SERVICE, BUT this buildup has caused cam failure on this car, a real nice 02 325XI. Any ideas or suggestions would be helpful, and will the cam assembly unbolt from the head on an e-46, just leaving the head in place and change out the cam stuff. I have not got that far yet, and never have taken one of these apart.
thanks, hushpuppy

Manolito · 02-10-2013, 10:29 AM

No, but I would love to know what kind of oil that dealer has been using.

Does the sludge look like water was involved (gray?). If so, make sure all the PCV tubing is clear, and the drain hose from the PCV valve is intact.

If this is like an e36, which it likely is, I believe these cams are hollow and extremely fragile. No worries about taking them out since these cams are toast anyway, but you need to carefully follow directions for bolting in new ones if you don't have the BMW tool. Pelican has a how-to post on this I think.

You will need to thoroughly clean the sludge out of the VANOS, so you may as well change the O-rings and check the bearing in the VANOS while you are at it.

hushpuppy · 02-10-2013, 06:21 PM

Its actually a hard lacquer type of build up on the cam saddles and on top of the head. not gooy at all. The service records did not identify the oil used, but I'll bet they are sweating if more of their customers experience this. I have not gotten around to unbolting the cams and even try to clean this stuff off. Hopefully the bottom end is ok
thanks, hushpuppy