Heater Valve Replacement

[Burdekin]

Anyone replaced the heater valve? If so what's involved in fitting the temp sender unit in the heater matrix? Can it be done in-situ?

[142 Guy]

My first piece of advice is with respect to fitting the temperature sender - don't bother. That little device implies a level of control sophistication that does not really exist in the 140 interior heating system. If you need to replace the valve because it has become inoperative, I would be inclined to snip the existing capillary tube for the sensor leaving the old sensor in place and the use a clip or some other means to fasten the new sensor to the outside of the heater - someplace where it is not going to flop around and mess up the throttle mechanism - Oops, forgot that is not going to be a problem on RHD cars.

Full disclosure, I replaced mine; but, I did it with the heater out of the car at the time of the restoration. My memory is poor and I can't remember whether the sensor sits on top of the heater core or below the heater core. I "think" it is below the heater core in which case it may be possible to install the new sensor while leaving the heater core in place. On my 142, I believe that there is room between the top of the drivetrain hump and the bottom of the heater housing (that contains the flaps) that would allow you to drop the bottom of the housing to access the sensor. The bottom part of the housing is retained by clips along the sides. Getting those clips off in-situ will be a treat and I expect that getting them back on in-situ will be a triple treat. In order to get the bottom part of the heater housing off you will have to remove the lower valence. The fuse panel can stay in place because it is attached to the mid section of the heater housing. On an LHD car I would want to remove the glove box to facilitate access. I suspect that you will need to disconnect the two control cables to the flaps in the lower housing. You may be able to drop the lower housing down just enough to access the sensor. I cannot remember how the sensor is fastened to the core. If you need to completely remove the lower housing then I expect you may need to remove the shifter if you have the long forward mount shifter.

I have a photo from my restoration which shows the heater installed in the car with no dash. You can see the capillary tube entering on the left of the heater around the part line between the middle and lower heater sections which makes me think that the sensor is below the heater care. I can post the photo if you are interested.

[Burdekin]

The valve has started leaking after my trip to England. How much control does the sender unit/tube add? Leaving it out would certainly make it a much simpler job. I bought a NOS one a while back which was advertised for the 140 but the tubes are in the wrong position, could take apart and rotate so would be closer but still not totally correct. A pic would be great thanks.

[142 Guy]

The amount of additional control is undetermined. I tend to operate the temperature at all the way off (summer), mid way or all the way on. Mostly all off or all on. Presumably the feedback is there to adjust for changes in coolant temperature as the engine load changes in an attempt to keep the air temperature constant.

I found some photos of the heater unit while it was out of the car which are probably more useful. Sensor is clearly below the heater core. I can still post the photo with the heater installed in car with no dash if you want.

I don't understand the comment about the tube on the valve being in the wrong position. Also, remember my car is LHD; but, I thought the heater arrangement was the same for RHD

[Burdekin]

Originally Posted by 142 Guy

The amount of additional control is undetermined. I tend to operate the temperature at all the way off (summer), mid way or all the way on. Mostly all off or all on. Presumably the feedback is there to adjust for changes in coolant temperature as the engine load changes in an attempt to keep the air temperature constant.

I found some photos of the heater unit while it was out of the car which are probably more useful. Sensor is clearly below the heater core. I can still post the photo with the heater installed in car with no dash if you want.

I don't understand the comment about the tube on the valve being in the wrong position. Also, remember my car is LHD; but, I thought the heater arrangement was the same for RHD

Thanks. I tested the one I have in hot water, it closes it a wee bit when hot, but not very much. The intake and off take nozzles/tubes are 180degrees out on the one I bought previously so facing the wrong direction to fit the hoses to.

[Burdekin]

Does anyone know if the 67/68 valve will fit a car? Is it just the orientation of the inlet and outlet pipes that is different? https://www.classicvolvoparts.co.uk/...j-BFTrW0-g0GiQ

[142 Guy]

Originally Posted by Burdekin

Does anyone know if the 67/68 valve will fit a car? Is it just the orientation of the inlet and outlet pipes that is different? https://www.classicvolvoparts.co.uk/...j-BFTrW0-g0GiQ

Can't advise directly. I expect you would need to get the matching heater hoses. Depending on where your existing valve started leaking, it might be rebuildable. The valves are made by Ranco and Balkamp makes replacement seals.

https://www.napaonline.com/en/p/BK_6...rHGvTq8Xqz-_2-

Rebuild details are on Ron K's site

https://www.sw-em.com/Heater_Control_Valve.htm

Or, since the 679480 valve seems to have really departed from production, figure out how you can do a sanitary installation of one of these
https://www.ipdusa.com/products/4935...9131998-112976
You can find similar valves just by themselves for less than $20. I have seen them installed inside the engine compartment on a 140; but, the valve was fitted in by using big loops of heater hose to get it connected and it looked a proper bodge. Show us the way on how to do a sanitary installation.

[Burdekin]

Spoke with Brookhouse and the earlier one is interchangeable, just a small difference in the nozzles.

I will rebuild the old one with the other one I have and keep as a spare.

[Burdekin]

Got the new one in place. Used 142guy’s pics as a guide and drilled a 3.5mm hole for the temp sender tube in front of the original tube which I just cut off. Hopefully doesn’t rattle too much. Started raining so still need to connect the cable and refill the system.

[142 Guy]

Originally Posted by Burdekin

Spoke with Brookhouse and the earlier one is interchangeable, just a small difference in the nozzles.

I will rebuild the old one with the other one I have and keep as a spare.

Are they interchangeable without having to replace the heater hoses that attach to the valve?