535d noise

[Razvan]

Anyone might have an idea about this noise? While in gear is present constantly between between 2000 and 2500 while accelerating moderately.

I'm a mechanic, just rebuilt the engine but the noise was there before and noticed nothing wrong. A little axial play in the small turbo but as far as i'm concerned it sounds like an air leak somewhere, not a turbo whine.

20180220_124040.mp4

[Bimmer Owners' Club]

Hi Razvan...welcome to the Forum

Difficult one to pinpoint the cause ..... first thoughts were of the turbo bearings failing but not so sure as it only hits the spot at certain revs and it was bearings it would evidence throughout the rev range.

Thinking it may be an induction leak (inlet manifold, hoses, intercooler, etc) but don't discount an exhaust leak (anywhere from the manifold, turbo and through to the downpipe).

Maybe a smoke test is the best way forward....that would narrow down the possible causes almost immediately.

Let us know what you find

Cheers,   Trevor

 

 

[Razvan]

The intercooler has been changed, the inlet manifold is ok, the noise comes from the turbo side. I'll get some brake cleaner around to see if there is anything unusual today

[Razvan]

Doing 7.3s to 60mph at roughly half throttle(gear change at max 4000rpm). If i accelerate harder i actually get slower times

[Greydog]

I recall reading something some time ago where there was a similar issue, if the old grey matter isn't failing me there are a couple of "O" rings on the output side of the small turbo.

Apparently if they are disturbed they should be replaced as they never seal quite right again and there is an air leak on the pressure side. 

 

[Razvan]

I'm at 3.2 bar and high tempersture sealant has been applied to the o rings..

[Greydog]

Certainly way down on performance for a 535d, as your experiencing issues above half throttle is the large turbo boosting correctly if the small turbo is over-boosting it may cause the big one to stall?

Clutching at straws a bit but hope it helps

Dave

[Razvan]

Ordered the small turbo, should receive it wednesday, hopefully that's the problem :)

[Bimmer Owners' Club]

let us know how it goes...be nice to see if that resolves it

[Razvan]

Just changed the turbo today, same poo. Removed the dpf and egr completely a couple of days ago. What i can tell so far is that the manifold and turbos are ok, 100% sure. I'm thinking of an actuator now as there isn't really much thing to change from now on..