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Hey my brother text me today asking if I could change his water pump. He said his 1997 Chevy Cavalier is blowing cold air with the heat on and is overheating shortly after he turns the car on. He thinks its the water pump not circulating but he doesn’t really know anything about cars.
I’m thinking it may have a bad thermostat, blockage in heater core, or heater switch that’s not working properly( the one that allows coolant to flow back to the heater core, I dunno if this this car has one though.)
What are your thought’s? If I change the water pump i’ll do the thermostat too but I don’t want to change the pump and the car still overheating?
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Buy the replacement thermostat. Take out the old one and boil it on the stove to see if it is opening as it should. Water pumps rarely fail except when the seals or bearings fail and they leak coolant. The 97 probably does not have a heater control valve (IT WOULD BE ON THE HEATER HOSE NEAR THE FIREWALL). There is a motor or cable on the Heat/AC box that regulates temperature by moving a “Blend Door”. These are common points of failure. Usually accessed behind the glove box, you can manually open the damper if you remove the motor / cable. Work on the overheating issue first.
Make sure the radiator and engine are full of coolant and purged of air then warm up the engine and feel the heater hoses where they enter the firewall. They should both be hot. If one is warm and the other cool, the heater core is stopped up.
Yea but he let Dex-COOL sit in the system for like 10 years straight never changed it and it completely corroded the system out. I believe those blades on the water pump may also be corroded and not pumping coolant as efficiently.
I changed the thermostat and he says the engine isn’t heating anymore and he does seem to be getting heat pretty well. Hopefully it stays like that!
The first step in any cooling system diagnosis is to purge the system of air. In fact the symptoms you describe sound very much like air in the system to me. I’m not saying you don’t have other problems but I always recommend starting with bleeding the cooling system first.
Thanks a lot boys! I changed the thermostat an it ran fine for a wekr so but eventually died. Its alright he didn’t take car of it! Thanks for all the help!
Thanks a lot boys! I changed the thermostat an it ran fine for a wekr so but eventually died. Its alright he didn’t take car of it! Thanks for all the help!
10 years without changing the coolant, even dex-cool? Dex cool is kind of hard on gaskets anyways.
Honestly, by the time the thermostat failed, the rest of the engine probably had more problems than a third world country. Nothing you could have really done by then.
There is a reason why maintenance is necessary.Makes me wonder – how do shop mechanics handle it when someone brings in their car and the thing rotting from bumper to bumper (like my sister’s car)?
Sorry to hear it worked out that way. If you don’t take care of them they just don’t last. Thanks for the update.
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