Coolant is running out the car, replaced the water pump yesterday, coolant still flowing out, after the car is crunk about 5min..do you think I need a thermostat?? Or what could be the problem
My car has 128000 miles.
My car has an automatic transmission.
A thermostat is a good first step with overheating issues, usually because it's inexpensive and easy to replace. So it's always good to eliminate that as a possibility, but I think you may have more problems then that. I presume you mean that coolant is running out of the overflow tank. This happens because of excessive pressure in the cooling system. It can happen if the coolant is low, because air pockets in the system cause hot spots where the remaining coolant will boil. It can be difficult to get all of the air out of the system so that's a possibility especially since you just changed the waterpump. It can also happen if there is combustion pressure leaking into the cooling system as it does with a bad head gasket.
When you change the thermostat, find a heater hose or some other small cooling hose near the top of the engine and disconnect it. Refill the engine with 50% diluted coolant until coolant runs out of the hose you disconnected, then hook it back up. Run the engine with the defroster on maximum until you feel heat coming out of the dash vents, checking the coolant level periodically. When you feel good heat, you know the engine is full. If you continue to have a problem, contact YourMechanic and they will send a technician to your home to diagnose your cooling system and tell you what you can do.
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