A noise that speaks for itself
A rubbing, scraping or metallic grinding noise coming from the turbo – especially under acceleration or deceleration – almost always means the impeller wheel is touching its housing. This is an advanced stage of bearing wear: the shaft has so much play that the wheel is no longer centred.
Stop driving immediately: fragments of the wheel or housing can be drawn into the engine and damage the pistons and valves.Likely causes
- Bearings worn due to a lubrication fault: insufficient, degraded or contaminated oil, or a blocked oil feed.
- Wheel damaged by a foreign object drawn in on the compressor side (filter fragment, nut, debris) or on the exhaust side.
- Turbo pushed beyond its limits (aggressive remapping, boost control fault).
What to check before fitting a new turbo
- The source of any foreign object: air filter, hoses, manifold.
- The condition of the intercooler and hoses – clean them if debris has passed through.
- The oil feed and return lines, and the quality of the engine oil.
- The condition of the engine if debris may have been ingested.
What if the engine has ingested debris?
An endoscope inspection allows you to check the condition of the pistons and valves. If they are damaged, a reconditioned engine on an exchange basis, supplied as a bare engine and warranted for up to 24 months, is generally the safest solution.
