We replaced the thermostat, intake gasket ,clamps, and water pump, the heater core was bypassed.. There are no leaks and no coolant loss. There is a faulty temperature sensor though. The upper radiator hose tends to have pressure on it. I repeat the coolant level stays the same. The temperature gauge tend to bounce around the it will say it's overheating but when I check the engine is cool to touch. It runs just fine when the lines after the lines are bled. I'm at a loss right now. No smoke and a new cap on the coolant jug.
My car has 246000 miles.
My car has an automatic transmission.
Either there is still air in the system causing steam which will make the sending unit spike to the high levels or the coolant temperature sensor - sending unit is not working. If a coolant temperature sensor - sending unit is not working, the coolant temperature gauge will move around and cause a multiple output reading. If you have replaced the coolant temperature sensor - sending unit and the temperature gauge is still moving around and there is no air in the cooling system, then the gauge cluster in the cab would need replaced as there is a direct short to the coolant temperature gauge.
If you need further assistance with your coolant gauge bouncing, then seek out a professional, such as one from Your Mechanic, to help you.
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