Hi,
I've owned our 92 940 sedan for about 3.5 years. I can't remember for sure about the first winter but I don't think it has ever heated well since we have owned it. Much lower performance than our 240s. There aren't any issues with the cooling system- engine temp looks good, never overheats, etc. At highway speeds the cabin will warm up fairly well (with recirculating) but if I am idling, it doesn't really get warm inside, even though engine temp is good. Defrost never gets close to warm because I can't recirculate- struggles to melt off snow and ice. We're in central Illinois- recent temps have been about 5-25 degrees most days.

Here's what I've done:
1) During the first winter I smelled some coolant so I replaced the heater core with the FCP Groton core in the spring.
2) I replaced the control valve with one from FCP Groton. I currently have it rigged so it stays at max flow to make sure it isn't a problem with the control system.
3) I changed the water pump. I thought this was the problem because the one I removed appeared to be machined badly at the return line from the heater so that the opening was only about half of what it should have been. This helped but it still doesn't seem like it heats well. I think replacement was a Hepu.

Two questions:
1) Is this performance typical of other 940s? As my wife says, they wouldn't settle for this in Sweden.
2) The fact that it heats ok at highway speeds but barely does in stop and go traffic (with a warm engine) makes me think there is some circulatory problem going on. Either a problem with the new water pump or a restriction somewhere that the higher pump volume/pressure gets through. Does this seem likely? Any ideas what to check?

Thanks!
Lyle