Increase in the amount of oil in the engine – what is the reason and how to fix it?

BMW driver question

In my car, the oil in the oil pan is arriving, in addition, the exhaust smells. The on-board computer does not show any errors. What could be the reason for such faults?

The problem affected a 2007 BMW X3 with 80,000 kilometers, but it may also occur in other models.

BMW X3 xDrixe | By order_242 from Chile (BMW X3 Xdrive25i 2010)[CC BY-SA 2.0], via Wikimedia Commons

Response from BM Cars service

Increase in the amount of oil in the engine can be caused by wear of the cylinder face or baked piston rings (in older models). In new models equipped with a diesel particulate filter (DPF), this is a common phenomenon caused by operation of the vehicle for short distances (frequent ignition and extinguishing of the engine). This way of operation triggers frequent activation of the program mode for afterburning of soot particles accumulated in the filter. The engine injection system is then instructed to extend the injection time. Some of the unburned fuel then enters the oil sump and causes a slight increase in the amount of oil. This is where the different exhaust smell can come from.

If the right oil is used in the vehicle in operation, the amount should be closely monitored and changed more often due to the loss of viscosity parameters. A full diagnosis of the vehicle will help to determine the fault in detail.

BMW X3 E83

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• Freshly replaced DPF in BMW, clogged again in a short time – what is the reason?
• DPF in BMW – problems and repair of diesel particulate filter in diesel cars
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