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Q: Cooling system

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Earlier today, I had white smoke coming from under the hood. I stopped and looked to find one of my heater hoses popped off and coolant and leaked out. I brought it to a mechanic and he told me that my thermostat was closed shut and that was creating pressure and thats why it came off. He told me that replacing that thermostat and a plastic piece inside of the hose that cracked would be okay and I should be good to go. Thoughts?

My car has 79000 miles.
My car has an automatic transmission.

A: The thermostat is a commonly known part to ...

The thermostat is a commonly known part to fail causing the coolant to not flow through the radiator properly causing the engine to overheat. The diagnosis sounds about right and is consistent with a thermostat failing. This can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds.

When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. I would suggest having an expert from Your Mechanic come to your home to diagnose your cooling system.

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