[Watsey]

My 330d started using oil around 1,000 ago (ish), as much as 500ml per tank of fuel (400-500 miles). Total mileage is just shy of 100k.

The BMW Indy which looks after the car said that the first 'go to' cause would be leaking turbo oil seals, so I removed the IC and found that the boost pipe from the turbo was wet with oil.

The car was then taken to the same Indy for the turbo to be removed so that it could be couriered to a turbo reconditioning / hybrid turbo specialist. At that stage the Indy confirmed an oil leak from the turbo. Engine oil leaked seemingly from the hot and cold sides simultaneously, although obviously the engine was not running when the turbo was being removed.

The turbo was rebuilt to a strengthened spec : new shaft, new bearings and oil seals, billet compressor wheel. I'm told that the turbo was placed on a balancing rig which also required a pressurised oil supply (obviously) as the turbo was spun at 132,000 rpm for balancing. No problems were noted, and the turbo was despatched back to the Indy.

The turbo was then refitted by the Indy. As part of the refitting process the engine oil and filter were changed, the turbo was spun by hand to make sure that it was ok, and the engine was cranked several times (without starting it) to make sure that it was fed with oil before the engine was run.

The engine was started and the car was taken for a short road test before having a final inspection before it was 'passed' for release.

During the final checks an oil leak was noticed from the turbo at the v-band which connects the turbo to the DPF.

The turbo was then removed from the engine again and several photos were sent to me for discussion.

Hot side 'in' from the exhaust manifold : dry, only soot present. This suggests that oil is not coming from the engine I.e. it's not coming from worn rings / pistons.

Hot side 'out' : wet with oil.

Cold side 'in' : clean and dry.

Cold side 'out' : clean and dry.

The CCV has been checked and is not obstructed. The same goes for the oil flow and return to/from the turbo.

The turbo will be sent back for inspection and further testing on Monday but I'm interested in input from forum members that may have seen these problems previously.

[eugene89us]

Thank you for such an awesome write-up, I am looking forward to hearing updates and subscribing to this thread for any other suggestions. Of course, you remember my plight with turbo seals leaking, but correction of PCV blockage in my case eliminated my issue completely. That was about 20,000 miles ago for me. It sounds like you have tested all possible culprits, such as lack of restriction in oil supply/outflow and proper operation of PCV valve. Hopefully this additional turbo inspection will get the leak corrected. Sounds to me that after the initial rebuild, the cold side leak was eliminated, which is certainly a good sign. Since otherwise, you'd continue having leaks on both ends if another culprit were the issue given that these turbos would leak even brand new if there were underlying issues with oil outflow due to oil passage restrictions or high crankcase pressures. Keep us posted please!