MB-E320-CDI

I have an E320CDI(should have the OM642 engine). How long should one let the engine idle with a cold(-5 Celsius/23 Fahrenheit or lower) weather? I have read that one should not let the modern cars with fuel injection sensors to idle at cold because the engine works in rich mode(more fuel is pumped into mixture) when cold and extra fuel works as a solvent for engine oil.

kajtek1

I no longer live in such cold weather, but even when I did, I started driving immediately when engine would run with no hesitation.
On old carburated cars pushing gas pedal would kill cold engine, but being soft on clutch I could start rolling on 1st, than 2nd and by the time I was ready for 3rd the engine already warmed up enough.

Strigoi

It doesn't get anywhere close to being that cold here, but I always drive off once the car drops down from the high idle. I take it easy until they're fully warmed up.

rapidoxidation

Got the '05 CDI in my driveway. Temps range from 100F in the summer to -40F (rarely) in the winter. I sometimes start the car and let it warm, sometimes I start the car and drive. Depends on how much of a hurry I'm in. Either way, I don't worry about it BUT I don't drive it hard until I see at least one bar on the temp gauge.

Strigoi

It's better to go by oil temp instead of the water temp. The water gets up to temp way before the oil on my E63. It shows to take it easy until the oil hits 80°, which usually takes 4-5 miles of driving.

kajtek1

some years of SL class don't have coolant temp gauges, but oil temp gauges. Now $10 BT adapter can display that on your android.
Still there is long way from rolling a car with cold engine to racing it.