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I realized the heater core in my D2 runs continuously, dumping hot coolant back into the pump without the chance to be cooled by the radiator. This was resulting in temps reaching 220* on long highway inclines in Colorado until running the cabin heat at full blast.
I bought some 3/4" silicone coolant lines and a simple valve to turn off the flow when heat to the cabin isn't needed. Works very well, and I no longer see elevated temps, in combination with my custom electrical cooling setup.
I want to do something like this on my D3. I think it is silly the heater cores are always hot. I get that is it needed for proper blending of heat and that in theory the blend door, if fully closed, keeps the heat at bay. But realistically that core is emitting heat and warming up parts of the dash while at the same time I have my AC on full blast. Heck, even my 73 Lincoln had a vacuum controlled valve to stop the flow of coolant to the heater core. The mod I want to do however would be with an electrically controlled solenoid with a dash switch. In Wisconsins there are too many 80 degree fall days that drop into the 50s at night and I dont want to have to pull over to get my heat working.
^ my cabin gets hot a lot just because the flap doesn't fully shut and I can feel warm air coming out. One concern is that the heater core itself is a radiator. If your engine starts to overheat, you can turn on the heat to full blast and get a bit of extra cooling. It's helped me out in a pinch a few times.
^ my cabin gets hot a lot just because the flap doesn't fully shut and I can feel warm air coming out. One concern is that the heater core itself is a radiator. If your engine starts to overheat, you can turn on the heat to full blast and get a bit of extra cooling. It's helped me out in a pinch a few times.
This is actually a bit of a misunderstanding. Part of the reason your engine starts to overheat in the first place is because, with the cabin heat off, the heater core dumps un-cooled coolant back into water pump without reaching the main radiator. By shutting off the heater core flow, there is no longer un-cooled coolant in the system, it all goes to the main radiator, avoiding the initial overheating all together. I'd consider it a design flaw, in my amateur opinion.
Simple Heater Core Shut-off Mod
