Heat stopped working 1974 corvette
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Instructor
Joined: Jan 2017
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Heat stopped working 1974 corvette
On my 1974 corvette, my heat suddenly stopped working. I was driving to work during a cold day and about halfway there the heat shut off and cold air started blowing(it hasn't worked since). I need help in diagnosing this problem. Any ideas?
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Hi and welcome.
There is no shut-off valve to stop the flow of water.
Heat is controlled by a flap in the heater core box.
Check that the temperature cable is connected on both ends.
Heat is controlled by a flap in the heater core box.
Check that the temperature cable is connected on both ends.
Team Owner
Joined: Aug 1999
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From: Ontario
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Michael S. Palmer
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From: Beaver County PA
Is your coolant level low? Is the engine running hot? If the level is low or the thermostat isn't opening completely, you won't be getting any hot coolant to the heater core and the fan will blow cold air.
Le Mans Master
Joined: Aug 2006
Posts: 7,431
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
That would be an easy fix.
Or is the thermostat stuck open and the engine is running too cold?
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From: Duvall, WA
Thread Starter
Instructor
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Temature cable.
[QUOTE=Peterbuilt;1593882509]There is no shut-off valve to stop the flow of water.
Heat is controlled by a flap in the heater core box.
Check that the temperature cable is connected on both ends.
Does the temperature cable also direct the airflow? Like wether the air goes to defrost or feet, or face? If so, then mine is ok because when i spin the wheel to heat, the air goes directly to my feet.
Heat is controlled by a flap in the heater core box.
Check that the temperature cable is connected on both ends.
Does the temperature cable also direct the airflow? Like wether the air goes to defrost or feet, or face? If so, then mine is ok because when i spin the wheel to heat, the air goes directly to my feet.
Thread Starter
Instructor
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The thermostat is fine and the radiator is full of coolant. I just topped it off a few weeks ago.
Thread Starter
Instructor
Joined: Jan 2017
Posts: 175
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[QUOTE=DUB;1593889461]Does you car have A/C???
How hot is your coolant getting when you drive now after this problem started???
My a/c is broken, the hose connected to the VIR valve is leaking. The cars engine temp varies with outside air temperature. When the outside air is around 50 or 60 degrees, the engine runs around 160-175 degrees.
How hot is your coolant getting when you drive now after this problem started???
My a/c is broken, the hose connected to the VIR valve is leaking. The cars engine temp varies with outside air temperature. When the outside air is around 50 or 60 degrees, the engine runs around 160-175 degrees.