Bad Thermostat

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
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Valley of the Sun
A sudden, straight to "hot" over heat after about 5 mins on the road = stuck shut thermo

A slow steady temp build-up = partially open thermo

Slow for the coolant to warm up = stuck open thermo
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
1
38
Valley of the Sun
Doesn't happen?
Why don't you just post exactly what it's doing vs us playing a guessing game?
 

Dunckel

Active Member
Jan 16, 2007
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Spokane, WA
Heat up a bowl of water to 200*F. Place the Tstat in the water. After a few seconds, the valve should start to open. As the temperature of the water falls closer the the operating temp of the Tstat, the valve should start to close. If the thermostat fails to open even though the water is above 190 degrees, you probably have a "stuck closed" situation.