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      09-21-2009, 01:15 PM   #1
Hang up and drive!

Drives: 335d
Join Date: Sep 2009
Location: Miami

iTrader: (0)

Diesel Engine warm up and cool down time


Waiting to receive my 2010 335d and saw some discussion elsewhere about warm up/cool down periods. Can anyone say exactly what does the manual say about this?

Typically it is always good to give an engine a minute or two to warm up and cool down before putting in gear. I'm sure many folks don't do that.

I know some diesel cars actually have a shut off timer built in, that after you remove the key the engine keeps running for approx 1 minute to cool down the turbo. I certainly understand why you may want to do this, but is it built in that way on the BMW?

Most cars actually idle a bit higher when you first start them, then after about 30-60 seconds they slow down, and that is when I usually engage the gears. I also usually wait about 15-30 seconds before I turn off my engine, and that is with a gasoline engine, with and without a turbo.

I've heard that some engines (diesels and gas) with a turbo can have turbo damage if you shutdown with the turbo too hot, i.e. you were driving hard and then shut it down. As I recall the concern was that the housing and rotor are still rather hot and the oil stops circulating around the bearing, perhaps leading to a seizure.

Appreciate hearing what facts (or myths or urban legends) if any are out there about this on the BMW diesel engine.