Packard Forum Index » Pre-War (1899-1942)

My car is missing the lines and the valve for the heating. Where do I install the shut-off valve?
Greetings Mike

You did not mention a model for your 37 but typically the shut off valve is located at the water outlet port on the head. There are two service letters with articles that give some info on heater plumbing for 37 cars. The second one has a photo of an engine where you can see the valve.

Letter 1

Letter 2

The hot water outlet to the heater core and the associated valve should be in the cylinder head, a bit more than half way to the rear

Thank you for your answers.
I wanted to install the valve in the picture.
I can't see a valve anywhere on old pictures. How was the original?
Greetings Mike

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You will need to find a run of hose straight and long enough to cut and insert that type valve. Ideally the shut off valve should be in the line between the supply port and heater. In the factory layout the short length between the head outlet and heater inlet would be about the only place. If you eliminate the hard tubing over the engine for the return side and just use hose then you could place the valve in the return line as a less desirable location. There would be more options but you will need to figure how to route and clamp the hose so it does not fall on the manifold or be subject to other damage. Don't believe clamping the return hose to the inner fender as later cars did is an easy option on 37s because of the lift up hood.

Here is the photo from service letter 2 linked above which shows the factory valve located in the white circe at the outlet port on the head. A similar type valve was used thru 47 although the shape of valve and angle of outlet port varied slightly. I cannot speak for the size valve your 37 needs but on later cars the thread for the port in the head is 3/8 NPT and outlet is for 5/8 hose. Yours may be the same but you would need to verify.

Similar working and looking universal type heater shut off valves to the originals are still available at many parts stores but if you need the 3/8 NPT thread, that requirement narrows the style and availability considerably.

Here is the factory photo and a view of a few of the valves Napa carries. Napa appears to have stopped listing the dimensions on their website so no idea if any of their valves have the 3/8 NPT thread. I bought a similar valve for my 47 from another parts store.

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On my former prewar Packards which went back only to 1939, the valve was always threaded directly into the head with the outlet at 90 degrees. I probably even have an original somewhere but it would be at my Oregon shop.

very interesting.
I thought the water pump line was the pressure line.
does it matter for the system which hose I put the valve in?

Greetings Mike

In theory it should go in the supply line to shut off water going directly to the heater core. That way if the heater core sprung a leak it could be shut off and damage would be less likely to happen than if the supply was still present as it would be with the valve in the return line.

On most Packard inline engines from mid 30s on the water pump outlet goes into the block, water goes up thru the head where the heater port is located and then out the opening where the upper radiator hose connects to the radiator. That makes the head port the pressure side for the heater. The heater return goes back to the water pump and you will find that port is on the return side of the pump.

that makes sense.
although I think that the new valve is not 100% tight.