High oil burn in BMW 1 – causes and how to fix it?

Driver’s question – combustion in BWM 1

I bought my BMW about two months ago with a mileage of 150,000 km. I noticed a significant loss of oil about 1 l per 1000 km. Mostly, the car while driving does not smoke somehow significantly. On the other hand, when I reach the traffic lights and start dynamically or when I add gas, a cloud of bluish smoke rises behind the car. It only appears on a warm engine. Could I ask for some advice? What could it be?

The problem occurred on a BMW 120i E87 with a 150 hp N46 engine, but it may also occur on other models.

BM Cars service response – high oil consumption faults in BMW 1

The design of the N46 engine and its workmanship mean that it customarily consumes about 0.3-0.5 liters of oil per 1,000 km. This is the oil consumption/fuel consumption, assuming I have no leaks.

After a mileage of about 70-100,000 km, there is an additional problem with a clogged air purge and its lines. A faulty crankcase vent causes oil to be forced into the intake manifold and burn extra oil combined with kicking during acceleration or after even a short stop with the engine running.

If this is the case, the solution to the problem is to replace the scavenge with lines and clean the intake manifold. After mileage of 100-150,000 km, it is also very common to see worn valve seals and baked scraper rings on the pistons.

Both of these symptoms result in a significant increase in oil consumption of more than 1 liter per 1,000 km and additional strong kicking while driving. Removal of the defect requires replacement of the seals (usually combined with disassembly of the engine head) and replacement of a set of piston rings. The operation is time-consuming and expensive. Despite this, it does not provide a full guarantee that the defect will be removed due to (sometimes) excessive wear of the cylinder heads in the engine block.

Making an accurate diagnosis requires performing a full engine diagnostic.

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