radiator overflow tank?

[41/53dodges]

hello all,

i installed a 66' mustang radiator in my truck and to make it fit, it had to sit lower than the original, making it lower than the heater core. would it be advisable to add an overflow tank and how would i do it?

[JBNeal]

The original truck radiator upper tank sits higher than the factory heater installation to keep coolant pressure (due to gravity) to force air out of the system. Essentially, the radiator drains towards the engine & heater. If the rad.upper tank is lower than the heater core, then coolant will want to drain from the heater to the radiator all of the time. So if an overflow tank is installed, it needs to be higher than the heater core & rad.upper tank. My concern is that with the heater higher than your rad.upper tank, then coolant will want to drain out of the overflow and the non-pressurized cap.

[olddodgeguy]

If I remember correctly, it seems in the Thunderbirds of the early 60's they had a problem with the radiator being lower than the engine so they went with a separate holding tank and radiator fill with the cap on that tank rather than the radiator tank. We once had a sprint race car with the same problem and built a tank out of an old radiator by removing the upper and lower tanks and soldered them together. That gave us the inlet and outlet we needed and we then just plumbed it into the system. Once we bled the air out of the system it worked great. Just a suggestion for your problem. Mike