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