As the new A4 will becoming with the stop / start option it got me thinking....

How will the stop / Start feature affect the life of the Turbo??

Turbo's need the oil circulating to carry the tremendous heat away. After a hard or not so hard run your EGT (exhaust gas temps) should be reduced before shutdown. Of course no one specs their apparatus/cars with EGT gauges.


Glad the below text from another forum to save me re-writing something similar.)
The main reason is to allow the turbo to spin down from the very high RPM (100k rpm isn't unusual) that it spins at while it's still being fed oil by the mechanical oil pump in the engine. Shut the engine off before it's had a chance to spin down and you cut the oil feed - that's what ruins the bearings.

It's the same for petrol turbo cars, although they typically have the turbo begin working at higher RPM than a diesel (my Tdi hit's peak boost at around 1,800 RPM whereas my old MR2 turbo it was closer to 4,000 RPM) you can avoid prolonged idling (also bad for the engine btw) by simply driving it nicely for the last few miles of your journey and avoid heavy turbo usage.

Some turbos (no LR ones to my knowledge) are liquid cooled by the engine coolant although the second generation MR2 turbo certainly was and heat soak from the turbo could, potentially, boil the coolant in the turbo if the engine was shut down without allowing the engine to idle and cool the turbo off first. This coupled with the oil stavation could ruin the turbo, or in extreme cases blow the turbo coolant piping which leads to a total coolant loss - if you don't notice before driving it again (I know... but you'd be amazed at what some people don't notice) you could kiss goodbye to the head gasket, the head or even the whole engine.

TD, Tdi and TD5 (sorry, don't know about the TDV6 and 8's) Land Rover engines do not feed coolant to the turbo and spin down will take less than 30 seconds. If you've been using the engine and turbo very hard (long uphill for example) immediately before shutting off, give it the full 30 seconds before you
shut it down

i expect that many TDI or "T" owners dont allow the turbo to cool down after a hard or long drive but with the option of the car stopping and starting when you stop surely this is going to allow the turbo not to displace heat if you let it idle.


I would be interested on peoples thoughts with this.....

Rick