Most car manufacturers recommend warming up with a light load by easy driving instead of idling. Is this true for the diesel engine in a 300SD?
The engine seems to run cold and takes quite a while to warm up. Is this a typical characteristic of diesels?
As soon as the oil pressure is up get going. These diesels will not warm up idling and must be driven, idling a cold enigne will carbon it up.
My 80 300SD warms up about as fast as any other car I've owned. In fact, I'd say I get cabin heat faster in this car than in most others. I've always driven it after starting up, without waiting, unless it's very cold, like under 20. Then I keep it idling a little faster than normal, just at the point where it runs smoother for a minute or so before driving off. Then I take it easy for the first 5 mins or so, while it warms up.
If yours takes a long time to get to normal temp, I'd change the thermostat.
Start it and drive off.
My diesel takes longer to reach 80 degrees C. than my gas car but that's the nature of a diesel's thermal efficiency vs. gas engines, IMHO.
Thomas Lambach '80 300SD, owned since new
theres a whole lot of cast iron to warm up but i get OK heat after 2 miles and 80C at around 4 miles.
case
the case, minus a few cans!
I wait about 30-45 seconds on my 81 300td. The oil is always pegged, and the engine has a good, solid sound. I agree that it's a Looonnnngggg time to get the thing warmed up while idling, even on a warm day. However, I do try not to jump out of my parking lot and do 60 at full acceleration while cold.
The general advice is as already stated, to drive off immediately (or within a very short space of time) but gently until operating temp is reached. From previous discussions on this topic here it seems that the 'real' operating temperature is reached about 5 min after it says so on the dashboard instrument.
DAS
Correct, this is what MB says. Idling to warm it up just clogs the prechambers with carbon.
MB says to never idle the engine for more than 5 mninutes at any time.
The engine is fully warmed up when the oil is at temperature, not the coolant. This is why Ferarris have oil temperature gauges.
Not to mention only warming up part of the engine/transmission system giving rise to different metal expansion etc.
DAS
For direct contact replace nospam with schmetterling
Have something to add? Share your thoughts — no account required.
Ask the community — no account required