Water Cooled Turbos

[isham-research.freeserve.co.uk at pop.pol.net.uk]

> I thought the main reason behind letting the engine idle for ~1 minute after
> coming to a stop was to let the speed if the turbo slow to a reasonable
> amount with oil pressure still there because the turbo bearing need's oil
> pressure the same way a big end does ?

No, the turbo slows VERY quickly when you come off the loud pedal.  The
bearing doesn't have the same need for pressure that a big end or main
bearing has, but it does have a need for flow.  That's why avoiding
constriction - especially of the drian back to the sump - is very
important.  The problem arises when sitting oil is 'cooked' by residual
heat, but it manifests itself when the turbo is under stress.

The return line from the bottom of the turbo to the sump is not that
hard to access and worth a check every now and then during an oil change.

--
 Phil Payne
 http://www.isham-research.freeserve.co.uk/quattro
 Phone +44 7785 302803   Fax: +44 7785 309674