[FnoFFen]

Is this still valid for modern turbocharged engines? What some says is the turbo should be able to reduce its spin when the engine i still running at idle. This is to ensure cooling of the oil or something.

I have heard it is recommended to let the engine run 30 seconds at idle before turning it off after normal driving and as much as 2 minutes if the car has been driven hard.

What do you day? The instruction manual says nothing about this. Is it a myth ?

[lmaleke]

Originally Posted by FnoFFen

Is this still valid for modern turbocharged engines? What some says is the turbo should be able to reduce its spin when the engine i still running at idle. This is to ensure cooling of the oil or something.

I have heard it is recommended to let the engine run 30 seconds at idle before turning it off after normal driving and as much as 2 minutes if the car has been driven hard.

What do you day? The instruction manual says nothing about this. Is it a myth ?

What I do is that I slow down everytime I'm about 5mins away from home or office or any other destination, and when I arrived I let the engine cool down for a minute or so prior to turning it off; for diesels or otherwise

[gspannu]

Originally Posted by FnoFFen

Is this still valid for modern turbocharged engines? What some says is the turbo should be able to reduce its spin when the engine i still running at idle. This is to ensure cooling of the oil or something.

I have heard it is recommended to let the engine run 30 seconds at idle before turning it off after normal driving and as much as 2 minutes if the car has been driven hard.

What do you day? The instruction manual says nothing about this. Is it a myth ?

Been driving BMW diesels for more than 14 years now. Total miles driven is well in excess of 200,000 miles. My oldest BMW diesel did 140,000 miles before I sold it, and from what I know, the new owner has put in another 40,000.

Have never taken any special precaution fork the turbos. What I definitely do is give the cars a spirited drive every now and then, but nothing special for the turbo cooling specifically.

[kave]

The only time i have done that is after a track day. Never else.
This was the procedure in the early days of turbo, remember the Saab 900 Turbo? That wasnt diesel powered but still has lots of turbo issues.

[Dandle]

I let the engine idle for a little while if coming from had driving i.e. long trips on motorways etc. Otherwise I don't bother, as others do I let the engine have an easy life for the last little bit of the journey and just turn it off once its at idle.

[DDarkEnergy]

Modern cars run with synthetic oil and turbos are water cooled so little or no chance of burning the rotor axle as was the case when turbos were not cooled and the oil was mineral that "carbonizes" at much lower temperature than synthetic oil.
Thus the need in early turbos to idle in order to cool the rotor axle.

[fre2bpowerless]

It probably shouldn't matter now but I let her idle for a minute or two, I drive with a light foot for the last km to my place as well.

I remember reading something about turbos and oil temps a long time ago and follow this routine ever since.

[HighlandPete]

Originally Posted by Dandle

I let the engine idle for a little while if coming from had driving i.e. long trips on motorways etc. Otherwise I don't bother, as others do I let the engine have an easy life for the last little bit of the journey and just turn it off once its at idle.

Same here, just that extra bit of care to help things along.

As a general note, diesel engine exhaust gas temperature (EGT) is not as high as a petrol engine anyway, so there is not the same issue as in a hard worked petrol engine. I'm a little more careful with my 535i, than with the diesels.

HighlandPete

[SomeRandomer123]

^ Yeah as Pete says, it's all about looking after the turbo regardless of whether it's diesel or petrol. I hear the pumps required to run keep running when the engine is "ASSed" of off, but does the circulation of oil continue whilst the engine is shutdown?

[Dandle]

From what I've seen the is an electric waterpump to keep water flowing but the oil pump is mechanical so there is no oil flow with the engine off.