Some small cooling systems can be quickly overcome by cold air rushing thru an open grill; This is why you will sometimes see 'winterfronts' on some vehicles. Even cardboard in front of the grill will help.Make sure your radiator is full; even if it is a little low it will make a huge difference in it's ability to maintain heat as cold air rushes thru it. I hope this helps you. Mark
The pointer on a thermostat moves when the room temperature changes. This change in temperature causes the thermostat's sensor to detect the difference and adjust the pointer accordingly to indicate the new temperature reading.
The temperature blend door may be at fault.
could be your thermostat is stuck or perhaps and needs to be replaced.
The thermostat opens in response to the engine reaching a certain temperature. It is designed to regulate the flow of coolant through the engine to maintain optimal operating temperature.
If the temperature goes up and down and the coolant level is ok your thermostat is probably sticking. Replace the thermostat and you should solve the problem.
The Thermostat and Temp and Press Valve is faulty and needs to be replaced. or the PRV (pressure reducing valve) is dirty and must be replaced
this could be as a result of failed thermostat, since they now fail-safe ie they're opened to allow water to circulate freely.
change the thermostat
There are a few possible reasons your temperature gauge may not be working after replacing the thermostat in your Mercury Topaz. It could be due to a faulty temperature sensor, a wiring issue, or a malfunctioning instrument cluster. I recommend checking these components for any issues and ensuring they are functioning properly.
Sounds like blown head gasket.
the reason why the coolant is spilling up over the reservoir is because the thermostat needs to be replaced because when the engine needs water the thermostat heats up from the engine and causes the springs to expant which opens a seal to allow the water throughout the engine i just realpaced the thermostat in my volkswagen
A thermostat works on a bi-metal strip. The strip consists of two different metals that contract and expand at different rates. This causes the strip to bend as it heats up or cools down. This action triggers the thermostat to switch an appliance on or off.