Thanks for all the great info you guys sent me! It looks like I may have a bad heater control valve, not a leaking heater core after all. So, any tips on replacing the control valve? I noticed the original OEM valve on the '83 240s has been replaced by a newer version. Is there any modifications needed to install the new version? Thanks!

Yes, but everything you need for the modification is included with the new valve. At least it did in the one I got from FCP Groton. I haven't installed it yet - kind of looks like a PITA.

You can still get the old style valve at www.importpartsspec.com - cost around 30 - 40 bucks if I remember correctly. I'm not sure the pros/cons of the new vs. old installation.

And you are right - it is a pain. Some tips:

1) Open the heater control all the way and drain the coolant - I didn't - big mistake. Coolant everywhere.

2) I would replace the hoses leading up to this part. Hey you're down there anyway. But get the hoses first! The hose that runs from the firewall to the HCV is difficult to find. Draw an accurate picture of what this sucker looks like, the bends are pretty sharp. I had to find a heater hose from a foreing parts store that looked really close, than hack an end off. For the HCV to heater core I just used stock hose, the bends aren't too bad at all. Sorry don't have parts numbers for you. I think the size was 5/8 inch heater hose, but double check.

3) Get a lot of towels, line the area around the floor with em for when you take the hoses off.

4) Get a piece of sturdy foam stuff for your knees. Either that or lay down upside down on the seat.

5) The heater valve has a thermo assembly that fits into the left half of the blower assembly. The left side of the blower case is held on by these little metal clips. You can slide them off and split the blower case just enough (1/4 to 3/8 inch) to remove and install this termo assy.

6) When you refill the car with coolant, make sure heater valve is fully opened and you pinch hoses, whatever you have to do to allow the air to escape. Can't say I really enjoy the Volvo cooling design in this respect, no air bleed that I've seen.

Enjoy the wonders of variable heat for the winter.

Colin-

Thanks for the tips. The new valve kit came with one new heater hose and doesn't use the thermo assembly - just a simple bigger-hole-to-smaller-hole valve. I guess I should track down the other hose (there are just two of them down there, right?).

Can't wait to have a fully functioning blower, and controls next week.

Is the hose that was supplied with the kit small (~ 6")? If so than that depending on the alignment of the new valve that should be the only special hose. The other hose can be fashioned from stock heater hose, since the bends going up to the top of the heater core (access from glove box) aren't that great, and there is a little room to play around with. This hose is sort of long, I would get about 3 feet and string it down through the glove box, connect to brand *new* valve, then cut the upper portion to length.

Yeah, the new hose is small and compensates for the position of the new valve. I'll get some generic heater hose for the other. Thanks.

The only thing that I can suggest is not to break the little copper capilary tube..... if you do... just resolder it very carefully.

Richard.