Q: How can the rear main bearing oil seal be replaced after removing the transmission and flywheel from the BMW Z3?
A: The crankshaft seal can be replaced after the transmission and Flywheel have been removed from the engine. Note the radio security code and disconnect the negative battery cable. Raise and safely support the vehicle. Remove the transmission. On manual transmissions, remove the clutch assembly. Remove the flywheel. Using a suitable seal removal tool, carefully remove the oil seal. Inspect the outer edge of the seal housing for nicks or sharp edges. Carefully chamfer the outer edge of the seal housing to remove any sharp edges or nicks. Coat the sealing lips of the new seal with oil and install the new seal into the end cover housing with a suitable seal installation tool. DO NOT coat the outer sealing surface of the seal with sealant. It should be clean and dry on the 6-cylinder engines. Press the seal in until it is about 0.039-0.079 inches (0.991-2.070mm) deeper than the standard seal which was installed flush with the housing. Install the remaining components in the opposite order from which they were removed. Lower the vehicle and connect the negative battery cable. Check and top off all fluid levels. Once the engine is started, check for any fluid leaks. Start the engine and check that oil pressure is present; if the oil pressure lamp does not extinguish within 5-7 seconds of starting the engine, turn the engine OFF.