cooling down a TDi before switching off?

[sleep envy]

have had petrol FA engines before which required me to let the engine idle for a while so the oil cooled before I switched the engine off

do I have to follow the same proceedure for an '05 A3 2.0 TDi?

[Dave80s]

Idling is to allow the oil to circulate around the turbo to cool it, so yes.

Although if you cruise home the last few miles without spinning up the turbo then that has the same effect.

[jcelee]

I used to work for an Audi dealer and went on the Audi UK technology course. They said that turbos needed time to cool in the old days when they were the size of buckets but the modern turbos (TDI & TFSI) were so small (around the size of a penny) that cooling / oxidising oil on the bearings etc really wasn't an issue....

[wildoliver]

[Dr G]

wildoliver said:

[jshell]

It's more to do with whether the turbo is water cooled or not. Early turbos, my WR quattro for example, had no water cooling so needed time to cool down with the engine running and oil still circulating. Later turbos with water cooling also have a timer delay on the water pump that circulated water after the engine is switched off - negating the need for a period of idling.

[matt3001]

I run a 2.0TDI 170 and I just cruise back the last mile, but I think this is something installed in me, I think that the cooled blowers these days don't really need it