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2002 grand cherokee 6 cyl coolant temp

In my 2002 Grand Cherokee, I replaced the water pump and the thermostat about a month ago. Ever since, the temperature of coolant doesn’t go up very high, it decreased about thirty degrees. I replaced the temperature sensor to a new one, replaced the thermostat to a brand new one but the same thing continues to happen. The temperature of the coolant does not go up to the original 195 degrees. When the engine is idle for a certain amount of time, it goes about 195 degrees. But when I drive, it goes back down thirty degrees. What is causing this problem?

Thermostats are designed to open at certain temperatures…perhaps the ones you’re using open at too low a temperature. You can often find multiple temperatures for the same model.

i’m sure it was 195 f thermostat.

There’s really nothing else that can cause an “overcooling” condition except for an incorrect (or stuck open) thermostat, or a problem with the temperature sender/gauge. You said you replaced the temperature sensor, which goes to the computer. Did you maybe mean to replace the temperature sender which is what goes to the instrument panel gauge?

I replaced sensor that goes to computer . Thermostat was replaced with brand new ones twice already . thanks for your replies .

How is the engine cooling system supposed to operate? Not sure? A mechanic could show you what to do and how to make the temperature checks with an infra-red thermometer. And, you’ll save money by NOT changing all those parts.