VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Replacing heat and def hoses and switch wire

Hi new VCCA member here name is Mike. I posted a few times on the new user forum and it was suggested here would be the better place to ask questions as this is the year range of my car. So for right now I am going to get the heat and def in order and I'm replacing hoses and going to rewire switches and most wiring as it is about shot. In looking at the install directions ruscar sent me, in my mind it seem the flow would be backwards. I'll just describe the way I see it. It shows the hose from the thermostat housing going to the left side of fire wall core then out the rt.side to under seat core then back to the water pump which I have a shut off valve on. There is two arrows showing that to be the flow direction. It just seems to me the flow would start at the pump and return to the thermostat housing. What am I missing or getting confused on. I have drained about 1 1/2 gal of antifreeze to get below the pump level and I flushed out the firewall core till it ran clean and am fixing to put the new hoses on. Could someone please help me make sense of this. Thanks Mike
Oh I wanted to add that the under seat core lines had been cut off and the shut off closed to the point of benting the tangs on it. I'm suspecting the core under seat might have a leak and possibly the firewall one too. I read in a post about 47 and earlier had 0 pressure caps. I was just running the garden hose through the def. core, there was no leak in the car and I couldn't tell under the hood as I got water every where. How much pressure would it take to show a leak?

Not sure if I got the routing of the hoses to the undercarriage right or not. I took them to and from through a space under the battery tray.

It depends on which heater was installed. The under seat heater has the hoses running under the floor.

Give me a few minutes and I will email you the complete instructions.

Just remember this is a very low pressure system so don't test with too much pressure.

Look at the water pump. The pump draws in water through the large hose from the bottom of the radiator, and if attached the small hose from the heater, then pushes it through the block and out the top where the thermostat is. Think that's right.

1942-1947 radiator top tank stamped 3115954 and filler neck not designed for a pressure cap.
1948 radiator top tank has #3121096 and is designed fir a pressure cap as the 1948 came with a pressure cap.
after 1950 the 3115954 was discontinued from parts stock and the 3121096 was sold for parts eplacement.

Hello Chev Nut; I have a 1947 Stylemaster 4dr that is stock with a front defroster unit and a under front sear heater unit. My heater hoses start at the thermostat housing to the in (top) defroster core and the out side goes the the hose back to the right side of the under seat core and out the other side to the pump{which is more than needed to say for my question}. The car has the stock cooling system BUT it has a 1961 235 pg engine,so does the coolent system need to be a pressurized??
Thank you for any comments!

I would like to hear the answer to that also David as I have a 1958 235 that I was planning to swap in the distant future. I have a question for you David, I also have the def and under seat heater. My under seat lines were cut off so I don't know how they were routed, do both your lines to and from under seat go under and back in the same place? OH and I have been trying to check for leaks, I back flushed the def with the garden hose and didn't see a leak there and I put the under seat in a tub of water and blowing into it. I didn't see any bubbles so I'm hoping it's good.

Just confirming my radiator is a Harrison and stamped 3115954. Also David your under seat core, do your lines come out of the core next to each other or one off each side? Mine are next to each other and on the outside passenger side. They have replacement core's they sell at The Filling Station three are too small and are core only, you need to solder them to your tanks. There is one says 39-50 accy under seat heater core and is a new replacement but there are no pictures or dimensions. I hope mine is good they want $500 for the replacement one.