1992 Buick Lesabre heater control valve?

Tiny
KEVINSCAR
  • MEMBER
  • 1992 BUICK LESABRE
VERY low heat coming into passenger compartment. Fan speed is fine, lots of air. All vacuum line checked, all doors (vent, ac, def. Heater) working properly. Including mixing door. I've traced the heater hoses from the engine to the firewall. I simply cannot locate the heater control valve. I strongly suspect this part to be bad. Can you tell me WHERE it is? Thank you.
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Saturday, November 10th, 2007 AT 12:49 PM

3 Replies

Tiny
HIDDENFALLS
  • MEMBER
Check the coolant thermostat to see if it is stuck open(normally closed for a cold engine coolant)

It's a little spring valve located on the engine block by the upper radiator hose, they cost around 2-5 dollars to replace
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Friday, November 16th, 2007 AT 1:02 PM
Tiny
KEVINSCAR
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Thanks HIDDENFALLS for trying. I looked at the thermostat housing you mentioned, but BOTH radiator hoses are hot, and engine is reaching normal temperature, so I don't think there is an engine thermostat malfunctioning here. And, there is NO vacuum hose, or even a wire to this thermostat housing, to control anything. I'm sure it's temperature controlling the flow to the RADIATOR, and not the heater core. Also, I should have stated, the TOP heater core hose is HOT, the bottom is only warm. I'm wondering if this model LeSabre even HAS a heater control valve, or if the mixing door (which works fine) is the only thing controlling the amount of heat brought into the passenger compartment. I'm leaning towards a gummed up, or clogged core. BUMMER of a job! Thanks. Rob.
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Saturday, November 17th, 2007 AT 4:24 PM
Tiny
KEVINSCAR
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I guess this was a 'tough one' as I didn't get many replies. I found the problem, and it was something I didn't want to do, but I finally replaced the heater core itself. VERY hot air coming into the passenger compartment now. It appears GM has gone the cheap route, and no longer puts 'heater control valvles' in these cars, but simply controls the temperature via the 'mixing door' which was (as I initially stated) working fine. This means clogged cores will be more and more common, as coolant, and all the goop that normally clogs old radiators will now be clogging heater cores, due to coolant ALWAYS flowing through them, not just when the heater control valve alllows collant to heat the core. Cheaper and cheaper.
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Tuesday, December 11th, 2007 AT 4:31 PM

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