This image shows a damaged turbine wheel base – look closely and you can see that the base has several sections cut out of it, which have been chipped off.
Damage like this is caused by excessive thrust bearing wear, which has caused the turbine wheel base to grind up against the heat shield – breaking off big pieces of the wheel base in the process.
This kind of damage will significantly affect the operation of any turbo, heavily reducing its effectiveness and efficiency, and is fairly likely to prevent the turbo from operating at all.
In cases like this, the only real solution is to replace the broken components, and to check and repair/replace the thrust bearing, as repairing the wheel base isn’t generally economical.
