I put a new (different) water pump on the engine, because it had an overheating problem. I flushed the cooling system very well and replaced the water with anti freeze @ 50/50. It still overheated and the coolant foamed up real bad. The temp guage needle stuck at high temp. Could it be a bad head gasket?
I don't think it has a thermostat because there is an overflow pipe coming out of the radiator which leads me to believe that it is a cascade cooling system and not pressurized. The crank case oil is not contaminated so i don't think it is a cracked block. The foaming of the coolant leads me to think the head gasket might be bad. Any ideas? thanks in advance for any advice

Do You own a car built by Durant? 1931 612 sedan

Hi Rick:

usually foaming indicates that the water pump is drawing air along with the water/antifreeze. I would not eliminate a damaged headgasket, and there are ways to test for leakage. A good garage mechanic should have the equipment to do this test for you.
You are right abut the Durant not having a pressurized system. You could try this. Get the car running, remove the radiator cap, and observe the flow of water into the top of the radiator. If the water pump is pushing more water into the top of the rad than is able to percolate down through the rad, your water pump will start drawing air and produce foam. . This would lead you to believe that the radiator is partially plugged and will definitly cause overheating.I would run the engine at various speeds for this test and make sure the vehicle is up to operating temperature to begin with.
Your engine could be equiped with an in-line thermostat. This is a thermostat that is inserted in the upper rad hose. In this case, you will get very little fluid transfer into the rad until the thermostat opens at whatever operating temperature your thermostat is calibrated at. Once op temp is achieved, you will see a pronounced increase in the flow.

Do You own a car built by Durant? Frontenac 1932

I had the problem of over heating on my 1923 Durant,
years ago. I had talked to Jeff Gilis about the problem, his suggestion was to run the engine until hot then place my hand on the Rad and feel for hot and cold spots. That was my problem I found cold spots, had rad cleaned out, problem solved. Simple soultion if that proves out to be your problem.