BMW 320I
12/2001
N42 Engine
Problem:-
This is a very expensive engine to work on due to the complexity of everything under the bonnet.
The cylinder head came off after an overheating incident and was reconditioned. After 2 weeks the owner returned the car with an oil leak at the back of the head, it appered to be coming from an oil gallery plug.
Cause:-
This plug is beneath the vacuum pump driven by the exhaust camshaft & is not oil but seals up the EGR tube running the length of the cylinder head. Our advice is that the vacuum pump will leak oil and the best repair is not to attempt to fit new seals but to replace the pump.
Cure:-
Replace vacuum pump
Note: To avoid disputes the head section in your shop should not refit this item (bag it) .
Also we picked up from our sources that when the head comes off this family of engines, the installer is strongly advised to always replace the crankcase ventilation valve (PCV) fitted under the intake manifold – otherwiseexpext oil leakes around the engine. (We wounder if this was causing the vacuum pump to leak).
Reference:
This is a 4 cylinder DOHC twin variable cam & variable inlet lift head and went out at $971.30 inc GST, the only parts fitted was valve stem seals the rest was labour. (Date of pricing April 2008).