how do i tell if my thermostat is stuck open?

i replaced it a few months ago, and the temp gauge had been dead for a while. now the gauge has magically come back to life, once in a while, and it reads a lot colder.

any symptoms, other than looking at the inconsistent temp guage?

anthony

i replaced it a few months ago, and the temp gauge had been dead for a while. now the gauge has magically come back to life, once in a while, and it reads a lot colder.

any symptoms, other than looking at the inconsistent temp guage?

anthony

It sounds like the ECT (Engine coolant temperature) sensor connector is loose or has corroded terminals. The ECT is located in or near the Thermostat housing.

It sounds like the ECT (Engine coolant temperature) sensor connector is loose or has corroded terminals. The ECT is located in or near the Thermostat housing.

i agree. i replaced the sensor a few months ago in the hopes that it might make it work. no go. the fact that the gauge now responds (inconsistently, but responds nonetheless) to acceleration suggests there is a loose connection somewhere. i just havent had the time to start picking it apart, but i will soon.

nonetheless, any ideas about how i could figure out if the thermo is stuck open? it isnt controlled by the ECT sensor, i gather.

thanks,
anthony

i agree. i replaced the sensor a few months ago in the hopes that it might make it work. no go. the fact that the gauge now responds (inconsistently, but responds nonetheless) to acceleration suggests there is a loose connection somewhere. i just havent had the time to start picking it apart, but i will soon.

nonetheless, any ideas about how i could figure out if the thermo is stuck open? it isnt controlled by the ECT sensor, i gather.

thanks,
anthony

About the only way for sure is to take it out and look at it. You might lose some anti-freeze, but if it is stuck open and it is revved up with the radiator cap off it will shoot coolant out the neck. I wouldn' advise doing it this way. Makes a nasty mess on the top of your engine. My thermostat was stuck open on my 97 and that is what happened to me.

i agree. i replaced the sensor a few months ago in the hopes that it might make it work. no go. the fact that the gauge now responds (inconsistently, but responds nonetheless) to acceleration suggests there is a loose connection somewhere. i just havent had the time to start picking it apart, but i will soon.

nonetheless, any ideas about how i could figure out if the thermo is stuck open? it isnt controlled by the ECT sensor, i gather.

thanks,
anthony

You are correct, the themostat is strickly a bi-metalic component and reacts to the water temperature, and not controlled by the ECT.
To determine if the thermostat is 'open':
With a cold engine the cold water flows from the bottom of the radiator into the engine, and the thermostat is closed preventing the water returning to the radiator thru the top hose. When the water in the engine reaches the temperature of the thermostat, it opens. You can 'feel' a significant temperature difference between the two hoses if the thermostat is working....if they are the same.....not working.
You can also pinch the top hose when the engine is cold, you shouldn't be able to feel the water pressure from the pump. As the engine gets warm and the thermostat opens, you should then feel the water pressure when you pinch the top hose.

You are correct, the themostat is strickly a bi-metalic component and reacts to the water temperature, and not controlled by the ECT.
To determine if the thermostat is 'open':
With a cold engine the cold water flows from the bottom of the radiator into the engine, and the thermostat is closed preventing the water returning to the radiator thru the top hose. When the water in the engine reaches the temperature of the thermostat, it opens. You can 'feel' a significant temperature difference between the two hoses if the thermostat is working....if they are the same.....not working.
You can also pinch the top hose when the engine is cold, you shouldn't be able to feel the water pressure from the pump. As the engine gets warm and the thermostat opens, you should then feel the water pressure when you pinch the top hose.

i agrre thatr is what it is