HEATER CONTROL VALVE

[ALBSURE1091]

I have a 69 A/C car with a 318. She was running hot so I bypassed the heater core/heater control valve and now all is well. Could the running hot issue be the heater core the heater control valve or both? When the heater hoses were hooked up they did not get hot at all. Now bypassed they heat up just fine and the car runs perfect. Possible clog in the core or valve? I read a few topics here about heater control valves and looks like a rebuild will be in order if that is the issue. Any help would be great! Thanks

[Nacho-RT74]

Honestly I can see any relation between a hot engine and a posibly heater malfunction... in fact when you turn on the heater, this could get colder the coolant and engine could run slightly colder

[Tilar]

Has to be a coincidence because as Nacho said the heater will make it run cooler. If the heater core or valve were plugged it would simply bypass through the water pump, which is exactly what happens when you close the heat control valve.

[ALBSURE1091]

I thought the same thing that's what is getting me. With the heater hoses hooked up normal the car runs hot and coolant will come out of the overflow. When I bypass the system it runs perfect. Makes no sense but that is whats happening and I don't undertand why. Thanks for the input

[Dino]

If the heater core, valve, or one of the hoses is clogged then coolant cannot make full circle.  Sounds to me that coolant is still going through, but not at its normal flow resulting in a hotter running engine.  If the heat inside is turned off then the heater valve is closed and coolant comes out the waterpump, through the hose to the valve and returns to the pump through the other hose.  If the car runs hot in this scenario with the valve closed then the hoses are the problem.  However, since they seem to run warm now you bypassed the valve, the problem must be the core itself. 

Time for a heater box rebuild maybe?

[ALBSURE1091]

I tested core and it seems free flowing. The Control valve on the other hand was toast. As I have read in several posts they do not make repos and need to be rebuilt. I contacted the guy everyone recommends but he has not gotten back to me yet. So for now I will drive with it bypassed. Spring is in the air!! Yes I agree the heater box looks like a rebuild in order. The A/C is working so I guess they are 2 seperate systems. Thanks for all the help!

[Nacho-RT74]

My car got FOREVER the heater system sealed on water pump outlets ( being in the tropic is not really needed ), and NEVER EVER got really hot because was sealed. There is not a logic reason to get a hoter engine due a clogged heater system.

just couple of months ago made to work the heater system ( new outlets without welded caps ) on my car just because I wanted, not really because I needed, and nothing changed.

To get a cooler engine thanks to the heater is because you get the heater blower working.

[ALBSURE1091]

I agree all the way Nacho. I actually bypassed the valve and ran the hoses directly into the heater core just to see what would happen. Like you said the heat works great and the engine temp was basically about the same. My issue was in fact a leak in the system as a few guys stated. She all good now. Just need to find or rebuild my heater control valve.