The problem
This BMW E Series with the N46 2.0 litre engine came to us with two complaints. It was blowing blue smoke, and it was using too much oil between services.
Blue smoke means oil is burning inside the engine. On the N46, one of the most common causes is worn valve stem seals.
What are valve stem seals?
Each valve has a small rubber seal on top. The seal stops oil from running down the valve into the cylinder.
Over time, heat makes these seals hard. They crack and stop sealing. Oil then leaks into the cylinders and burns with the fuel.
Common signs
- Blue smoke when you start the car, especially in the morning
- Blue smoke after sitting at idle, then driving off
- You need to top up oil often
- Oily spark plugs
- Low oil warning between services
Which BMWs have the N46 engine?
The N46 is found in many E Series models, including the E90 320i, E87 118i and 120i, E46 318i, and the X3 2.0i.
What we did
First, we checked other causes of oil use, such as the crankcase vent valve (PCV). Then we removed the valve cover, the Valvetronic parts, the camshafts, and the rocker arms.
We replaced all the valve stem seals with quality Elring seals. We did this without removing the cylinder head, which saves time and cost for the customer.
After the job, we put everything back, set it up correctly, and road tested the car.
The result
No more blue smoke. Oil use is back to normal.
Don’t ignore blue smoke
Burning oil is more than a smell. It can foul spark plugs, damage the catalytic converter, and cause the engine to run low on oil. Fixing it early costs much less.
How we can help
At WA Auto Service Center in Bibra Lake, we specialise in BMW. If your BMW is smoking or using too much oil, book an inspection with us today.
