In Reply to: '89 750il Engin Oil Leak posted by David Soo on December 24, 1999 at 12:40:07:
: I am usually good in figuring where oil leaks come from. I've changed the chain tensioner o-ring which fixed the leak from the front passenger side of the engin. I have also changed one oil host to the oil cooler which is responsible for the leak in the driver side front part of the engin. I have also changed the oil pan gasket. Since then, I had gone under the car five times and still could not figure out the exact location of the leak which resulted in oil near the middle to the rear part of the engin. Oil appears to come from the driver side and extends all the way to the transmission. The upper engin block is clean, oil appears on the lower engin housing. Do I need the change the gasket? BMW dealer told me that I need to remove the engin to replace that gasket. I also suspect the oil return host which is connected to the lower engin case through a fitting. Is there any o-ring in the fitting itself? I hate o-rings in a ten year old car. Thanks.
I had a slow oil leak for two years that was driving me mad trying to find it. It turned out to be one of the bolts holding on the crankshaft sensor on the front of the engine. Apparently, this is a common problem.
The longer of the two bolts passes through or into an oil channel in the block. Total time to fix about fifteen minutes. Add some thread seal to the bolt before re-installing.
Incidentally, my car is a '92 735i so I do not know if the crankshaft sensor is in the same physical location as the 750iL. One giveway on the 735i is oil on top of the A/C compressor.
1992 735i 166,300 miles