Okay the heater core question is not for my '69 & '70 Impalas though for my winter beater '86 Caprice sedan. I am not getting any heat at all, coolant level full, engine (rebuilt 1992 9C1 police 350) runs and drives smooth as glass with never any overheating problems. I changed out the thermostat and put my hands on both heater core hoses to the firewall when the Caprice was warmed up good. The RH heater hose into the firewall is hot enough where I can't put my hand on it more than a second. The LH heater hose into the firewall is ice cold.
I'd say the heater Valve isn't opening!!! Assume this puppy has A/C, so it could be motorized valve, vac. leak, bad sensor etc. Unless you have a manual it could be a "can o worms" not knowing how to trouble shoot!!!
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Some times I wake up GRUMPY, but today I let her sleep in !!!!!!!!BLACKSTOCK Ont.
You were right on, the heater core was plugged of rusty water. I flushed it out and noticed the heater control valve locked up also. I went ahead and removed the water pump,radiator hoses etc and stuck a pressure washer in the coolant channels. I never saw so much rusty water come out! Finally 2 hrs later the water turned crystal clean. I also backflushed the block numerouse times through the thermostat housing and flushed the radiator as well. I will button the Caprice up this coming weekend and let you know the outcome, thanks again.
You may know this but it's not uncommon on old cars for a core to start leaking after a good flush. I guess all that junk is sometimes acting as a stop leak.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
