Help: Thermostat / Heating Weirdness (cannot warm up!)
November 27th, 2021, 2:54 PM
#1
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Help: Thermostat / Heating Weirdness (cannot warm up!)
Help. My inherited 1993 Suburban 5.7L gas just won't warm up.
My only thought is that the thermostat is somehow leaking, as if coolant is simply pumping around it -- is this possible? I have zero evidence of it, but it's the only thing I can think of if the thermostat SHOULD work and the parts were right (seemed to be).
Any thoughts / ideas?
I'm at a loss, as this shouldn't be too complicated.
THANK YOU!
- Past several years, it always ran cool -- 110-130deg as indicated by the dash and confirmed by the luke-warm cabin heater. When the radiator is blocked off (temporarily), the engine warms up perfectly, cabin heater warmed up (toasty!!), and all seemed ok. I assumed a stuck open (or missing) thermostat.
- Yesterday, I replaced the thermostat. The old one was ugly -- rust brown. In its place, I dropped in a Duralast Gold 195degF Thermostat 15359DLG and placed over the top of it, FEL-PRO Thermostat Gasket 35062, based on the recommendation of my friendly car parts store. Fired it up, bled the coolant bubbles out, checked for leaks....
My only thought is that the thermostat is somehow leaking, as if coolant is simply pumping around it -- is this possible? I have zero evidence of it, but it's the only thing I can think of if the thermostat SHOULD work and the parts were right (seemed to be).
Any thoughts / ideas?
I'm at a loss, as this shouldn't be too complicated.
THANK YOU!
November 27th, 2021, 3:30 PM
#2
CF Monarch
Help. My inherited 1993 Suburban 5.7L gas just won't warm up.
My only thought is that the thermostat is somehow leaking, as if coolant is simply pumping around it -- is this possible? I have zero evidence of it, but it's the only thing I can think of if the thermostat SHOULD work and the parts were right (seemed to be).
Any thoughts / ideas?
I'm at a loss, as this shouldn't be too complicated.
THANK YOU!
- Past several years, it always ran cool -- 110-130deg as indicated by the dash and confirmed by the luke-warm cabin heater. When the radiator is blocked off (temporarily), the engine warms up perfectly, cabin heater warmed up (toasty!!), and all seemed ok. I assumed a stuck open (or missing) thermostat.
- Yesterday, I replaced the thermostat. The old one was ugly -- rust brown. In its place, I dropped in a Duralast Gold 195degF Thermostat 15359DLG and placed over the top of it, FEL-PRO Thermostat Gasket 35062, based on the recommendation of my friendly car parts store. Fired it up, bled the coolant bubbles out, checked for leaks....
My only thought is that the thermostat is somehow leaking, as if coolant is simply pumping around it -- is this possible? I have zero evidence of it, but it's the only thing I can think of if the thermostat SHOULD work and the parts were right (seemed to be).
Any thoughts / ideas?
I'm at a loss, as this shouldn't be too complicated.
THANK YOU!
November 28th, 2021, 10:03 AM
#4
CF Veteran
And you can test the thermostat on the stove in a pot of water. Use a thermometer to see when it opens.
Maybe you have a partially plugged heater core?
I assume you have a rear heat system in your sub - does that also run too cool?
Maybe you have a partially plugged heater core?
I assume you have a rear heat system in your sub - does that also run too cool?
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