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We have a 1993 Pajero 4x4 2.8 diesel vehicle which we use for towing a caravan as well as the normal town car.

Lately, while towing, we have noticed a whistling sound comming from the engine compartment which comes in arround 2,000 to 2,250 revs. Not loud, but only between these figures.

Below & above them, the motor noise is normal. No noise when not towing.

Any idea's ??

Brian

From the "Ask Jack" archives - 14 December 2009

The source of the noise may be a leak from the exhaust manifold gasket or turbo charger to manifold gasket.

This is specially apparent under engine load and eventually will become audible at idle without load.

Check for broken manifold studs that secure the manifold to the cylinder head.

When having the gaskets replaced, the manifold should be checked for distortion.

A distorted manifold can leak again in no time.