I am driving an 06 525i with N52B25 engine and has been struggling with this burnt oil smell in the cabin for the past 18 months.

The car used to have severe oil leak when I bought 2 years ago and I have done all the major maintenance/replacement to fix the oil leak including

- New valve cover gasket
- New oil pan gasket
- oil cooler gasket
- CCV and all hoses attached to it
- vanos solenoid and O-ring
- Valve stem seal

and alot other gaskets I could see on realoem.

The oil leak reduced significantly but I do have oil leak somewhere (couldnt see by the eyes/ engine pretty dry now). Especially whenever I go hard on the accelerator, there immediately a burnt oil smell in the cabin and if I continued to go hard then the oil level on idrive shows a small reduction.

Any advise where to tackle this since I almost give up on this oil leak thing. Thanks

 

from the recent research i did, could be broken alu vc bolts or oil filter housing gasket (if you have yet to do that). trying to figure out my nasty cabin smell as well.

 

​​​​​​I replaced the oil filter housing gasket already . Then it me check on the valve cover bolt. These are such a PITA

 

Are you seeing any visible smoke under hard acceleration? did you replace your rear main seal? what is your current mileage?

 

Get a pal to drive mine yesterday and I can see some white smokes coming out the exhaust under hard acceleration. My car is now around 90K miles and I replaced the valve stem seals at 86K miles.

Do you have the part number for main seals?