Thanks for the suggestions. The expansion tank is a little low - I'd actually thought of low coolant, but expected that the tank would have to be empty to get no heat - I'll fill it and see.

I'll try to locate the heater core and check the hoses. This car is a bit more cramped in the engine bay than my '84.

It does have an aux pump, but I should get some heat on the highway without it and don't get anything.

Thanks again.

Any more suggestions?

__________________
1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer