940 Heater Control Valve

[bob12]

On my non-AC '90 745 when the slide lever for heating is moved from cold through the range to hot it operates the water valve just before the matrix.

That valve opens gradually in 'normal' valve like fashion (and a Golf Mk 1 valve) in response to the slider position and, if you don't do anything else the heat gradually increases as the valve opens.

Other than that all you can do via the other slider is direct the heat to wherever you want it with the central dash vents cutting out as the heat increases.

The only other control is the fan which provides a gentle zephyr or hurricane .....

Bob

[TonyS9]

Ah found an old pic, there are 2 cables attached to the valve (sort of in-series). One could be the flap.

I'm still sure its a variable valve rather than open/closed.

[Ian21401]

There appears to be a difference of opinions regarding the original Volvo valve. There may well have been different valves fitted by Volvo but from my experience with the valve fitted to my car I have to concur with TonyS9 and Bob12. The control “shutter” within the valve moves proportionally as the heater control is moved. ( Original defective valve part no. VO3537062, possible Bosch part no. 0928400185 or 183. Replacement valve part no. VO9447892. ) If McGandalf’s heater valve is original, once removed from the car, as previously described, it should be possible to see the “shutter” and cause it to move by operating the appropriate lever on the valve. My valve had two control cables attached to it. The dashboard heat control moves the lower control on the valve, this moves a lever and concave cam which actually moves the valve “shutter”. The dashboard air distribution control operates the upper lever on the valve which in turn moves a flap somewhere in the heater housing.
My original valve was only leaking due to a deformed intake tube. Given that these valves are NLA I would seriously consider attempting some form of repair. If McGandalf can remove the valve I suggest he examine it to ascertain the cause of the fault and consider a repair if possible.

[ulf]

In the link you can see the damper arm with cabel which regulates the mix of cold and hot air. It is rather tricky to mount the heating valve in the housing which contains the extra wire bracket to the damper. The water valve opens totally at a small movement of the control wire from dashboard.
https://www.bildelsbasen.se/se-sv/Vo...a/ID-29973742/

[ulf]

See link for watervalve that fits none ac cars.
https://www.skandix.de/en/spare-part...valve/1001873/

[ulf]

https://forum.7900klubben.se/viewtopic.php?t=76279
In the link you will find pictures and text how to change heating valve for none ac 940:s.
It is written in swedish, I presume you have learned swedish as you drive a volvo.
The pictures can be viewed clearer by pressing on them.

[Laird Scooby]

Originally Posted by ulf

The water valve opens totally at a small movement of the control wire from dashboard.

Tack!

About the only bit of Swedish i know! ^^^^^

When our Volvos were made, a lot of British parts were used so as Brits, we didn't really feel the need to learn Swedish! (Hope the humour translates!)

The HCV you linked to fits left hand drive cars, it won't fit RHD cars - i know this as another member bought one to try and replace his heater valve and found it was almost mirror image and as such would have worked back to front if it worked at all.

[827Roverman]

Originally Posted by Ian21401

There appears to be a difference of opinions regarding the original Volvo valve. There may well have been different valves fitted by Volvo but from my experience with the valve fitted to my car I have to concur with TonyS9 and Bob12. The control “shutter” within the valve moves proportionally as the heater control is moved. ( Original defective valve part no. VO3537062, possible Bosch part no. 0928400185 or 183. Replacement valve part no. VO9447892. ) If McGandalf’s heater valve is original, once removed from the car, as previously described, it should be possible to see the “shutter” and cause it to move by operating the appropriate lever on the valve. My valve had two control cables attached to it. The dashboard heat control moves the lower control on the valve, this moves a lever and concave cam which actually moves the valve “shutter”. The dashboard air distribution control operates the upper lever on the valve which in turn moves a flap somewhere in the heater housing.
My original valve was only leaking due to a deformed intake tube. Given that these valves are NLA I would seriously consider attempting some form of repair. If McGandalf can remove the valve I suggest he examine it to ascertain the cause of the fault and consider a repair if possible.

My old heater valve was leaking due to the same as above, deformed hose tubes due to someone overtightening the hoses, I was lucky and got a new one off a club member, but I saved my old one simply because my mechanic told me the valve itself was not leaking, my leaks were coming from the hoses, so one of these days I'll get round to trying to do something with it, I'm thinking along the lines of warming up the plastic hose tubes and inserting a piece of 15mm copper pipe as a liner, if it works I'll then have a spare, I tested it by holding it under water, blowing down the hose tubes, blocking off one end, it showed no signs of leaking, David.

[827Roverman]

Originally Posted by 827Roverman

My old heater valve was leaking due to the same as above, deformed hose tubes due to someone overtightening the hoses, I was lucky and got a new one off a club member, but I saved my old one simply because my mechanic told me the valve itself was not leaking, my leaks were coming from the hoses, so one of these days I'll get round to trying to do something with it, I'm thinking along the lines of warming up the plastic hose tubes and inserting a piece of 15mm copper pipe as a liner, if it works I'll then have a spare, I tested it by holding it under water, blowing down the hose tubes, blocking off one end, it showed no signs of leaking, David.

Footnote ! I did make the same mistake as others, saw one on line that looked exactly the same, but needles to say it turned out to be for a L/H drive, so I have a brand new one for L/H drive, any use to anyone ?

[ulf]

I had problems with a leaking HCV on my -91 945. I broke the plastic housing for the valve when I tried to mount the heating valve in car. Then I set the damper halfway and had only the heating valve operated from dashboard. The result was that max heat on the dash control resulted in max cooling and vice versa. It was very tricky to get the right temperature in car due to the fast manoeuvre of the water valve. It ended up replacing the complete heat aggregate to an ECC unit (this includes removing dashboard among other things). I also had to fix wiring for speed, engine running and a couple of other signals. Now the heating system works very well except for AC which I have not fixed yet. I do nearly never touch the heat controls as it is now automatic. The fan speeds up when temperature sensor for heated air senses that it is warm enough for reaching the set temperature in car. Also after car has been resting half an hour the fan blows full until set temperature is reached, the fan also goes down in speed when the car reach approximately 30 mph. Anothe benefit for this change of heat aggregate is that the HCV moved to engine compartment and if it will leak in future it will not leak in passenger compartment.