Coolant Temp

[BigMo82]

Trying to find out if my thermostat is working ok and I have a question. Should the coolant in the plastic reservoir get hot once the car has warmed up? And if it doesn't does that mean the thermostat is shut open or closed?

Mo

[Druid Boy]

The plastic bottle is the expansion tank, just somewhere for the water to go when it expands as it gets hot. If you want to check your thermostat without removing it try this:

start the car from cold.

the radiator will be cold as will the hoses feeding it

as the temperature rises the thermostat will open to allow hot coolant to circulate through the radiator to cool

As this starts to happen you will notice that one hose heats up much more quickly than the other. That indicates that your thermostat has opened and is working correctly.

If memory serves correctly the top hose lets the hot water in and the bottom hose lets the cooler water out.

[BigMo82]

Thanks for the reply. Will try that in a little while.