Monday, October 24, 2011

How can I troubleshoot a Prizm water pump?

I just picked up a 1993 GEO Prizm that overheats. I changed the thermostat with no success. The water pump is not making any noises or leaking, but I suspect that could be the problem. I don't detect any water in the engine oil, so I don't suspect head problems. The top hose to the radiator gets extremely hot, but the bottom hose is cool. In this weird car, the thermostat is connected to the bottom radiator hose at the engine, which is the opposite of what I am used to. How can I figure out if the pump is actually pumping properly?



Another issue, which I don't think is the overheating cause, is the heater core has a leak in it. I put a can of stop-leak in the system to plug that up, but I am not sure yet if it is still leaking or not. Even when the car engine is really hot, no heat comes out of the passenger compartment heater anyway. Both problems existed before the stop-leak was added. I am thinking the passenger compartment heat problem is either a clogged heater core or a non-functioning valve that connects to the heater control cable. Any thoughts on this issue also? I was thinking I should just bypass the heater core by connecting the hoses where they go to and from the heater core at the firewall until I figure out the overheating problem.



Your input is appreciated.How can I troubleshoot a Prizm water pump?As for the water heater, disconnect the heater hoses, make sure the coolant system is full and start the car. If coolant flies out of one of the hoses, the water pump is fine. While the hoses are disconnected, run a garden hose through the heater core and see if there is good flow. If not, the stop leak or something else has plugged up the core. This might be the same problem with the radiator which will cause overheating.