The temperature gauge is going up and down.
Hello. If the coolant temperature gauge is constantly fluctuating then the most common cause of this is a bad thermostat. If the thermostat is sticking or not opening and closing right then this will occur. It can also be a clog in the radiator or a water pump problem. If the engine has never gotten too hot then the thermostat should be replaced first. If the problem persists then the engine should have a block test and then the coolant needs to be checked to make sure it is flowing. If it is not then the water pump may be bad.
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