ADVICE PLEASE smoke from exhaust

[sean j g]

just had full engine rebuild new turbos etc 2.5 model mental cost but have noticed pale blue smoke from right hand side exhaust any ideas!! mainly on start up and over run they have said bring it back 2 us let us have a look and diagnose and sort out just a bit concerned could this be turbo!! or even worse engine internal issues by the way car now running at 398 bhp!!!

[F.C.]

sean j g said:

just had full engine rebuild new turbos etc 2.5 model mental cost but have noticed pale blue smoke from right hand side exhaust any ideas!! mainly on start up and over run they have said bring it back 2 us let us have a look and diagnose and sort out just a bit concerned could this be turbo!! or even worse engine internal issues by the way car now running at 398 bhp!!!

Turbo seals unlikely if they have just been re-built or new.
On the overrun does the smoke appear when you re-apply the throttle or before?
If it's when you re-apply throttle, there's a chance it's a valve guide seal/s.
God forbid rings and such after a full re-build.
Take it back to the garage, also a second opinion from a "reliable" source could be useful.
F.C.

[sean j g]

thanks for info will take car back to garage but just wanted some second opinions as 2 your thoughts cheers again

[daddysumo]

Which garage did thew engine rebuild, the turbo overhaul and which exhaust system are you using ?

Steve

[sean j g]

noble motorsport did rebuild new turbos fitted custom made exhaust which they have said is ok

[mgbond]

sean j g said:

noble motorsport did rebuild new turbos fitted custom made exhaust which they have said is ok

do you mind me asking the cost for the Exhaust (also have a 2.5).

Bondy

[gadgeroonie]

sounds like a turbo to me

what power did the car make at the wheels ?

[joust]

sean j g said:

noble motorsport did rebuild new turbos fitted custom made exhaust which they have said is ok

I had this on the first of two rebuilds of my original M12 I'm afraid. The fact that it had to be rebuilt a second time tells you the story.

Same company did the rebuilds for the factory then as well.

J

[Alpinestars]

I thought blue smoke was oil which is burnt in the engine eg piston seals etc. Turbo failure leads to oil being pumped into the exhaust and being burnt in the exhaust, which usually manifests itself as white smoke?

[RobP]

Alpinestars said:

I thought blue smoke was oil which is burnt in the engine eg piston seals etc. Turbo failure leads to oil being pumped into the exhaust and being burnt in the exhaust, which usually manifests itself as white smoke?

yep.

[Jim O.]

Alpinestars said:

Turbo failure leads to oil being pumped into the exhaust and being burnt in the exhaust, which usually manifests itself as white smoke?

It depends on how the turbo failed. If the leak is on the compressor side, the oil will be pumped into the intake, where it's burned by the engine.

Getting back to the original question, it could be either a turbo or the engine. Compression and leakdown tests should let you know whether it's the engine. Checking inside the intake piping for oil will let you know if a turbo is leaking on the compressor side.