Reader Question: I have a problem with heat in my 1995 Chevrolet Astro Van. Blower works fine and anti freeze full thermostat seems to operate runs at about 170 degrees. I need help badly as I live in Minnesota and high today is 5 degrees.
Feel the two heater hoses. They should both be hot to the touch when the engine is at normal operating temperature. If they are, you probably have a control issue inside the dash or the dash selector switch.
If only one heater hose is hot, you might have a heater valve problem or the heater core is stopped up with rust and needs to be back flushed.
If heater hoses are hot, you might have either a thermostat problem or a restriction in the radiator that is not allowing the hot coolant to circulate through the system.
Here is more about heater cores: