At the Tarheel Chapter's annual "Turkey Tech" winterizing inspection clinic hosted by Leith BMW in Raleigh, a number of BMW 2002 and 320i's were found to be leaking oil from the distributor flange (mine included!). This is the aluminum housing bolted to the rear of the head which receives the distributor, otherwise known as the rear cam cover. To check yours, reach underneath and look for fresh oil. Don't confuse it with a possible leak from the oil pressure sending unit.
The culprit here is a gasket, p/n 12 11 8 630 039. Get a new one and a tube of 3M Brand Super Silicone Sealant, p/n 08661. You'll need a 1O-mm and a 13-mm socket. It's best to remove the distributor before removing the flange. Just set the engine at No. 1 cylinder, top dead center (rotor pointing at line marked on rim of distributor and notch on crankshaft pulley aligned with pointer), then unbolt and pull the distributor out. Remove the housing and clean both surfaces of old gasket material. Be sure everything is free of oil film by de-greasing with alcohol. Apply an even coat of sealer to both sides of the gasket, then re-install. If you can get a torque wrench back there, put 18 ft Ibs. on the 13-mm bolt and 8 ft. Ibs. on the 10-mm bolts.
Before replacing the distributor, pour a little engine oil down the opening to replace what you removed and coat the walls to facilitate installation. To get things lined up right, turn the rotor about an inch counterclockwise, then insert into the housing. When installed properly, the center of the rotor will again be pointing at the mark on the rim of the distributor.
Incidentally, I'm lazy. To avoid having to check the timing after such operations, I scribe one mark on the distributor clamp and another on the distributor base right at the clamp. Then, after inserting the distributor, I just line up the marks and clamp 'er up!
This operation is easy on a 320i because there is plenty of room. A 2002 will be a bit more difficult since the firewall will get in your way. One thing is for sure: if you've got a leak, you better fix it now before it gets worse. Things like that don't get better by themselves!
Author: Stan Simm