What tells the thermostat to open?
Once the temperature of the coolant rises to between 180 and 195 F (82 – 91 C), the thermostat starts to open, allowing fluid to flow through the radiator. By the time the coolant reaches 200 to 218 F (93 – 103 C), the thermostat is open all the way.
How do you tell if your thermostat is stuck open?
Symptoms of a bad thermostat Thermostat stuck open: When the thermostat is stuck open, the engine temperature drops below normal when driving, especially on the highway in cold weather. A stuck-open thermostat can also cause lack of heat from the heating system. The Check Engine light may come on too.
What happens if the thermostat doesn’t work?
Thermostats fail because they become weak, stuck open or stuck closed. When a thermostat is stuck open, coolant constantly circulates and the engine takes longer to reach operating temperature. This affects everything from performance to mileage to emissions and will ultimately take years off the engine’s life.
Why is the thermostat on my VW Jetta not working?
The thermostat on a 2003 Volkswagen Jetta opens and closes depending on the temperature of the coolant. When the thermostat fails, it gets stuck in either an open or a closed position. Either way, the coolant will store too much heat, and the engine could overheat as a result.
What to do if your Jetta is overheating?
If your Jetta seems to be overheating, one affordable option is to replace the thermostat. The thermostat is inexpensive, and replacing it is a straightforward procedure that you can do yourself using basic tools and materials. Park the Jetta on level ground and allow the engine to cool down completely. Lift the hood and prop it open.
What happens if your car thermostat is stuck closed?
Learn more… Your vehicle’s thermostat opens to allow coolant to flow through the radiator and cool the engine down. However, if the thermostat gets stuck in the closed position, the coolant can’t flow through the radiator and can make your engine overheat.
What to do if your thermostat is not working?
If your vehicle has a map-controlled thermostat, with a trouble code thrown by the engine computer, track down the cause with a code reader. Plug it into the OBD-II port and run a scan to see what the problem is. If the cause is the thermostat, replacement is the solution.