TSB's

Benz Overfill

On Mercedes-Benz gasoline engines, equipped with an oil level/oil pressure sensor, the instrument cluster indicates that the engine contains too much oil. The cause is likely that the vehicle is mainly driven in the city or used for short frequent trips where engine operating temperature might not be reached.

With frequent cold starts and lots of short trips, fuel can enter the engine oil in non-combusted form. Fuel outgassing through crankcase ventilation is only possible once the operating temperature is reached. If operating temperature is not reached, the ingressed fuel collects in the engine oil which in turn leads to a significant increase in the oil level. The reduced viscosity can cause engine timing malfunctions and the engine oil’s lubricating characteristics are reduced.

On vehicles that are primarily used for short trips, the engine oil level should be checked on a regular basis. Replace engine oil and filter.

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