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BMW Burning Oil Smell – Engine Oil Leaks – 6-Cylinder, M50, M52, M52TU, M54, Etc.

January 9, 2013

This answer is applicable for many BMWs in addition to the one listed below.

Q
car year: 2001
car model: 325i
Car has 185K miles.  After driving for a while we smell a strong smell of oil, like it is burning off the manifold. The thing is we don’t smell it all the time only once in a while. Can be on the highway or in slower traffic, doesn’t matter.

A
The smell is indeed likely leaking oil. We’ll point out three common oil leakage issues for the M50, M52, M52TU, M54, S50, S52 and S54 6-cylinder engines.  These engines are all based from the same design and are used in the 6-cylinder versions of the following chassis and models:

E36 3-series – 92-98, 323is, 323ic, 325i, 325is, 325ic, 328i, 328is, 328ic, M3

E46 3-series – 99-05, 323i, 323ci, 325i, 325ci, 325cic, 325xi, 328i, 328ci, 328cic, 330i, 330ci, 330cic, 330xi, M3

E34 5-series – 91-96, 525i, 525it

E39 5-series – 97-03, 525i, 525it, 528i, 528it, 530i, 530it

E60/E61 5-series – 04-05 sedans and wagons, 525i, 525xi, 530i, 530xi

E53 X5 – 01-06, 3.0i

E83 X3 – 04-06, 2.5i, 3.0i

E36/7 & E36/8 Z3 – 97-03 roaster and coupe, 2.3, 2.5, 2.8, 3.0, M

E85 & E86 Z4 – 04-05 roadster and coupe, 2.5i, 3.0i, M

Common oil leakage points:

1) Valve cover gasket – In addition to leakage into the spark plug wells the perimeter gasket can leak on the passenger side, spilling oil onto the exhaust manifolds, burning the oil.

DIY valve cover gasket replacement

2)  Oil filter housing to engine block gasket – When this gasket leaks it will wet the driver side of the engine block (above the oil pan) with oil.  As the engine block gets hotter, the oil can start to smell.

M54, etc., oil filter housing leaks

3) Crankcase ventilation oil separator and check valve assembly (Does not apply to M50, S50, S54) – The plastic oil separator section of this assembly can crack and allow oil to spill on the driver side of the engine block.  Additionally, the oil drain hose that is connected to the oil separator can crack and leak as well.

DIY Crankcase ventilation oil separator – check valve replacement

All of these points are common leakage areas for these engine models. We do stock all of the parts to repair these issues.  We would suggest that you inspect these areas and then, depending on what you see, plan your repair and order the appropriate parts.  The applicable Bentley repair manual will cover the procedures for these repairs.  Our advisers can assist in determining what is needed.  Just give us a call at 800-535-2002.

Bentley repair manuals:

 

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