My 1952 Hornet suddenly wants to overheat. Thermostat is 160. Engine wants to run at 190. Even with thermostat removed still runs at 190. Re-torqued head to 80 psi. I installed a radiator overflow tank which has less coolant each time I drive the car for 10 minutes or more. Water is going someplace but I don’t know where. Engine sounds and runs fine. I tested coolant for combustion gases x3 and tested ok. Does anyone have any suggestions?
First off, 190 degrees it not exactly overheating, especially of the outside are temps are higher. I have no idea where the car is located, so do not know the ambient temperatures in your area. In hotter temps, the 160 degree thermostat will be fully opened as it is designed to do. Does the higher 190F reading occur while idling , driving in slow traffic, or is it a problem at highway speeds? I do not recommend running the car without the thermostat, as it serves two inportant purposes: 1. coolant flow, 2. providing a restriction to control the coolant flow in such a way that the block gets pressurized by the water pump to raise the boiling point of the coolant in the block, to prevent vapor pockets from forming at the hotter spots (exhaust valve seats). Two years ago, you were mentioning hairline cracks in the valve relief area between the valves and cylinder prior to a planned rebuild. How did you address this? Also did you pull and inspect the brass water distribution tube behind the water pump that runs the length of the block supplying jets of coolant towards the exhaust valve seats? Aha, and the water pump itself.......is the clearance between the impeller and the back plate with the gasket installed at around 0.010"- 0.012"? This small clearance is needed to allow the pump to put out maximum head pressure......to big a clearance, the coolant will just flow back towards the suction side and the block pressure will drop.
I just saw this but on ken cates website he explains where to widen the cooling channels. I had this issue as well and my issue was the cooling channels were clogged up. Drain and remove radiator. remove the water pump and it will reveal the brass cooling channel. Take a pair of vise grips and lock it down tightly onto the brass channel and take a hammer and gently tap it out. at some point, you will need to loosen the motor mounts and jack up the front of the engine to clear the grill. Once out I took a powerwasher and went to town on the engine block and the brass channel. once completed if you do the updates to the channel this would be the time and then reinstall everything and test the engine. When I did this I had a ton of filth come out of the block as well as I reversed and flushed my radiator. hope this helps and sorry it took so long to see this.
Cheers
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