Odd Turbo Noise

[KitsonRis]

Got the replacement engine back in the car and its all working fine. Have done 430 miles in it.

I swapped the turbo from the broken engine as it has less miles than the replacement engine and I knew it worked properly. Last night I had a raft of error codes come up, most I think were old ones and related to the new temp sensor I put in being faulty and the timing going wrong when the cam belt tensioner failed.

I got the 17705 "Pressure drop between turbo and throttle valve" error code. I have cleared all codes and drove it today and none were thrown.

But since fitting the replacement engine with the original turbo, under acceleration the turbo makes a fluttering/two tone woosh. The harder you accelerate the louder the noise. Car pulls fine, averaged 42mpg over the 430miles, cruises fine, idles fine (now after replacement tmp sensor), not loud. I am not sure the turbo never used to make that kind of noise and was monotone. I have not had a chance to look at the pipe work yet being away from home with work now until the weekend.

[KitsonRis]

So it turns out this might not be turbo noise. 

Just had a good tinker with it and it sounds a bit more like an auxiliary driven something. It does make the noise all the time but very quiet in tick over. 

The only thing I haven't done since the engine swap is get the air con re-gassed. How does the air con pump work as the belt is still driving it, but does the pump still work when it isn't on? I did think it could be as thee is no fluid/gas it isn't being lubricated. 

[Saints92]

Air con pump is belt driven, if you remove the belt and the noise is still there then it's not that. 

[KitsonRis]

Did not think of removing the aux belt for a quick drive up the drive! Will do that tomorrow. 

It was more of how the internals work, as does it work and need lubricating etc even if off. 

 

More searching has has pointed to turbo to exhaust gasket, possibly pinking from not quite 100% timing. Tried to check all the connections that were removed, will give another check tomorrow