Four cylinder engine
Withdrawal
Disconnect the ground wire from the battery.
Models 316i from September 1988 and 318i from September 1987: Loosen both lower engine mounts and raise the engine just enough to pull the oil sump forward (see section «Removal and installation of the engine»).
Raise the car.
On vehicles produced since September 1984, unscrew the reinforcing frame.
Drain engine oil (see section «Engine oil change»).
Loosen the oil pan mounting bolts.
Remove the lower part of the oil sump; if required, pry carefully with a screwdriver.
Installation
Clean the contact surfaces of the upper and lower parts of the oil pan. Carefully straighten any bent contact surfaces on the lower part of the oil sump.
Models 316i from September 1988 and 318i from September 1987; coat the contact surfaces of both halves with a universal sealing paste, e.g. Curil.
Bond the gasket with a small amount of grease, check the fit of the gasket.
Install oil sump and tighten bolts by hand. Then tighten all bolts to 10 Nm.
If the reinforcing frame was removed, install and secure it.
Pour oil into the engine. There are two marks on the oil dipstick that determine the oil level in the engine. The difference between the MIN and MAX marks is 1 liter.
Lower the car.
Models 316i from September 1988 and 318i from September 1987: Lower engine and tighten engine mounts (see section «Removal and installation of the engine»).
Connect ground wire to battery.
After the test drive, check the tightness of the oil sump, tighten all bolts as carefully as possible.