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Cause
Poor fuel quality promotes faster oil ageing and thus a thickening of the engine oil
(oil sludging, predominantly in the cylinder head and sump).


Measure
In the event of a customer complaint, proceed as described below.

Generally applicable information:
BMW does not approve of any cleaning method that involves a flushing of the engine by
operating it with cleaning additives in the engine oil or by mixing diesel fuel with the engine oil.
Damage to the engine caused by this type of operation is not covered by the warranty.
This applies even if the flushing attempt is relatively short (e.g. 15 minutes) and at idling speed.

1) Procedure in the event of complaints concerning driving characteristics (oil sludging causing
idling complaints, misfiring, etc.):

- Read the DME fault code memory and clear it.

- Carry out an engine oil service.

- Change the coding to option 988 (maintenance interval level 2 coding = shortening of
oil service interval to 12,000 km):


CSL-S54.zip