Maniac (Heat doesn't work)


Old 01-29-07, 09:18 AM
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Maniac (Heat doesn't work)

I have a 1991 Pontiac Sunbird, and I have replaced the water pump, temp. sensor, temp. sending unit and thermostat. My heat still doesn't work. Can someone help me figure thisout?
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Old 01-29-07, 09:59 AM
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Check the hoses going through the firewall to the heater core when the engine is warmed up they should be hot/warm if they are then you have a problem with either heater core or controls, if they aren't you have a circulation problem and you will have to backtrack the hoses until you find where they get hot and fix the blockage. Check all the associated fuses etc. Have a nice day. Geo
Old 01-29-07, 03:28 PM
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Location: Hamilton County, Ohio
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There may be a mode valve and mode valve motor. It should be vacuum operated, so check for vacuum leaks. This would normally shut off the flow to the heater core when the air conditioning is running. If bad, could keep the warm water from circulating thru the heater core.

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