Rb25Det Blowing Smoke

[MissVader91]

Hey guys, I'm after some help! I've got a C34 RS4 (RB25DET) and it's been running sweet.
But we've been noticing that whenever I'm on a highway (Doing over 60km) and I start to slow down or brake the car is blowing white smoke which smells of oil... Not just a little bit like a cloud!
We put an oil catch can in it and it only helped for a few days.
My question is, Could it be the turbo seal?
I'm too scared to drive the car until it's sorted, I don't like yellow stickers

Thanks

[hairdryer33]

Got it in one

[Chris32]

Check your pcv valve is functioning

The catch can shouldn't make any difference unless there is excessive blow by being sucked into the inlet

[hy_rpm]

Valve stem seals

If it only happens under high vaccum situations