I have a 1971 Dodge Charger 500 with a 400ci and automatic transmission. not sure what the engine came out of (original 383 car). I have been having overheating / heat soak issues for a some time now. Driving down the highway temp stays steady at 180. If I come to a stop and shut the car off I can feel the coolant boiling / bubbling when I grab the top rad hose. I can also watch the temperature climb from 180 to as high as 215. That was out driving today with temps around 10C/50F. I have driven for over an hour before and temp stays good till I shut the car off. If I leave the car idling it will stay around 180 also. I think the issue is I have a hot spot in the block somewhere, like the coolant doesn't circulate through the whole block just keeps the front cool (by the temp sensor). Then when I shut the engine off the coolant temp balances inside the block to give me the high reading and the bubbling. I don't think it is a head gasket issue because I always have good heat from the heater core & don't smell any coolant in the exhaust. I do also have an electronic heater valve on the heater core. I do have an aftermarket ac system from vintage air installed also, but this issue also happens with out the ac on.
Things I have tried:
1. Upgrade Radiator from 22" Champion To 26" Griffin
2. Upgrade water pump from stock to high flow Milodon High Volume
3. Install proper fan shroud for 26" Rad
4. Hoard radiator in so air has to go through rad and not around it
5. Thermostats: 160, 180 & 195
Things it might be?:
1. Heater valve in the off position doesn't allow proper flow through block? (I have tried running without the heater valve and if I remember correctly it didn't help / I can try again)
2. Water pump not turning the right direction / impeller not working properly with housing?
I hope you can make sense of my rambling, any help would be great.
1971 Dodge Charger 500
400 BB
727 Automatic
Holley Sniper EFI
Vintage Air AC
