Possible turbo noise

[apc01]

Over the last year or so my 100 series - 1998 4.2 TD with 112K miles - has developed a progressively louder noise on acceleration that kicks in at around 1700 RPM under load.


The noise definitely sounds like turbine whistle and not mechanical.


Other observations: after a service and oil change 2000 miles ago the noise was much quieter. The noise also gets louder as the engine warms up and oil thins.


The noise only happens when the car is under load from 1700 or so RPM and not when revved out of gear at any RPM.


Aside from that I have not noticed any performance issues.


What could this be?


Thanks.

 

[apc01]

As a sequel to this I eventually had the turbo removed from the car, sent away to be completely reconditioned - bearings, balancing etc - there was no core damage - yet the same noise still persists.

I have owned the car from new and covered 115K in it and the noise only appeared 500 miles ago. While it is difficult to describe a noise, it is best described as a sort of sucking, rasping sort of noise as opposed to anything metallic. There are no other symptoms, no smoke from the exhaust etc.

I really would like to fix the noise once and for all - any idea what it could be?

 

[tjtfaulkner]

I would look for a leak in the intercooler system, may be at a rubber hose/hose clip.

 

[t1pper]

I would look for a leak in the intercooler system, may be at a rubber hose/hose clip.

Yes sounds like a intercooler or pipe work leak as the turbo pressure increases it becomes more apparent.

 

[apc01]

Yes sounds like a intercooler or pipe work leak as the turbo pressure increases it becomes more apparent.

Thanks very much both - I will have that checked out.

 

[nathanrobo]

As a sequel to this I eventually had the turbo removed from the car, sent away to be completely reconditioned - bearings, balancing etc - there was no core damage - yet the same noise still persists.

I have owned the car from new and covered 115K in it and the noise only appeared 500 miles ago. While it is difficult to describe a noise, it is best described as a sort of sucking, rasping sort of noise as opposed to anything metallic. There are no other symptoms, no smoke from the exhaust etc.

I really would like to fix the noise once and for all - any idea what it could be?

Out of interest what did the turbo rebuild cost and who did it please?

 

[Chas]

Definitely sounds like an air leak in the intercooler system.

 

[apc01]

Out of interest what did the turbo rebuild cost and who did it please?

My turbo was reconditioned by Midland Turbo: http://www.midlandturbo.com/

I was very impressed with the quality of their work and professionalism throughout and would highly recommend them.

The cost was £180 + VAT. Had Their been core damage to the turbo - there wasnt in my case - it would have been £420 +VAT.

That said I still have the same sucking, rasping noise under boost. People here suggest it is an intercooler leak, which it could well be, and looking for somewhere to take it for further diagnosis. Midland Turbo only handle turbo units, not the whole vehicle. If anyone can recommend a good turbo pace in the north or midlands who could troubleshoot this, I would appreciate it.

 

[Dave]

How do you know the quality of their work was good?