I have a 1971 Corvette Stingray 350CI, 270HP, Automatic Transmission, with Factory Air. My car does not generate any heat and I was told that my "heater Core" needed to be replaced. After checking some of the symptons about a heater core I do not see any leakages either under my car or leaks into the car near the heater core. I was told that doing a "reverse flush through the heater hoses" would help clear/unclog the heater core. I do not have a lot of money to do a full heater core replacement and would prefer to see if there is a less expensive choice I can do to either prove that the heater core is just bad or what could be done to fix my lack of heat problem. Any help you could provide would be great, thank you.
If your heater core is plugged up a symptom would be the outlet hose would be noticeably cooler than the inlet hose since water would not be flowing much. You might want to check this to confirm the diagnosis. You may also want to check if you have a heater core shutoff valve that has malfunctioned. (A lot of air conditioned cars back then had one.)
I reverse flushed the heater core in my old Jeep a few years ago when the heat stopped working. I connected a garden hose to the heater core's outlet hose and used it to push the crud out. Heat has worked fine since.
If you do this don't use too much pressure or you can blow a weak heater core. Your cooling system pressure is probably around 15 psi - household water pressure can easily be 3 or 4 times that much.
what was the Jeep's heater core plugged up with?
1999 Cherokee 4.0, the heater core had 20 years worth of built up crap probably due to spotty maintenance by previous owners.