Instead, regardless of how hot or cold the outside air is, the coolant is routed back into the engine block to guarantee it achieves its optimal temperature (about 190 degrees) sooner. A common engine thermostat's components include a washer-style reservoir and a heating/cooling element. As long as there's fluid in the reservoir, the heater core will always keep the fluid at a comfortable temperature. When the engine heats up due to lack of cooling, the heat from the exhaust travels through the thermostat to open it up, allowing more coolant into the system.
The most common symptom that your car's thermostat needs replacing is poor engine performance along with high temperatures. If you're driving a new vehicle and this problem arises, contact your dealer right away. They should be able to diagnose the issue quickly by looking at various parts of the engine, such as the radiator, heater core, and thermostat housing. If necessary, they can make some adjustments to improve engine efficiency during normal use while waiting for the replacement part to arrive.
If you know your car has suffered previous damage and these problems have been fixed by replacing parts, then it's likely that's what's causing your current issue.
The coolant will not flow through the engine when it is cold. However, when the temperature rises, the thermostat gradually begins to open. The thermostat will be completely open by the time the engine reaches roughly 200 degrees Fahrenheit. At this point, any remaining fluid in the system will be heated and lost. Once the engine reaches its normal operating temperature, the thermostat closes again.
The exact timing of the thermostat opening will vary depending on how hot the engine is running. If the engine is only warm to the touch, there is no need to adjust the thermostat. It will open as needed to allow coolant into the heater core and heat up along with the rest of the car. As the engine heats up, the thermostat will close until it can no longer shut off the flow of coolant into the radiator. At that point, it may have to be replaced.
If the engine is being driven hard and is very hot, the thermostat may close before it has a chance to open. In this case, you will need to wait until it gets cooler before driving home. The engine will then be able to re-open the thermostat and release some of the heat before closing it again. This process will continue until the engine has cooled down enough for you to drive home.
The thermostat is positioned in the engine compartment, between the engine and the radiator. During engine warm-up, this little temperature-sensitive spring valve remains closed. When the thermostat is closed, coolant does not leave the engine and circulates through the radiator until the proper operating temperature is attained. At that point, the thermostat opens and allows the coolant to flow back into the engine.
Closed thermostats can be caused by many things, such as old age or damage from debris getting into the system. If you are having cooling problems during engine start up, check the condition of your thermostat first. It may need to be replaced before you even begin fixing other parts of your engine!
A damaged thermostat will cause excessive heat build-up inside the engine during cold starts. This is because the coolant cannot escape out of the system when the thermostat is closed. So instead it heats up inside the cylinder walls due to lack of contact with those surfaces. This can lead to premature engine wear and failure.
To fix a clogged or damaged thermostat, you will need to remove it and have it repaired or replaced. A new thermostat will cost about $100 and usually lasts for several years with regular use.