Stuck themostat: I think?

[Midniteoyl]

The reason NOT having one could cause a slow overheat is because of pump cavitation. But, its unlikely at these low RPMs.

 

[MHarryE]

I can't say definitely for your particular system but many are made that will partially bypass the radiator f the thermostat s removed. To run our cooling tests to determine the true cooling capability we have special blocked open thermostats, use pure water for coolant, and run at laid until the temperature stabilizes. That way we can run a cooling test on an 80 degree day and extrapolate to determine how it will do on a 120 degree day. If we run with no thermostat the engine will stabilize at a higher temp because of some coolant bypassing the radiator.

 

[Baby Grand]

Mmmmmmmmmm. Crow tastes great!
I guess I learned something today.

 

[ovrszd]

Mmmmmmmmmm. Crow tastes great!
I guess I learned something today.

Heheheheh. I learned this lesson years ago when my eldest Son bought a Olds Cutlass 455V8. It was running hot and we discovered the thermostat was bad. Took it out. Car wouldn't heat up unless you headed down the highway at cruising speed for a few miles. Heat just kept building until finally it would boil over. Coolant was going thru radiator too fast.

 

[Midniteoyl]

I can't say definitely for your particular system but many are made that will partially bypass the radiator f the thermostat s removed. To run our cooling tests to determine the true cooling capability we have special blocked open thermostats, use pure water for coolant, and run at laid until the temperature stabilizes. That way we can run a cooling test on an 80 degree day and extrapolate to determine how it will do on a 120 degree day. If we run with no thermostat the engine will stabilize at a higher temp because of some coolant bypassing the radiator.

Interesting! Any reason why this is done? I know in older cars/trucks there was a bypass for the heater, but removing the stat didnt mean you would overheat... I cant see a reason for a tractor.

 

[TractorTech]

Overheating without a thermostat takes time, but once it starts getting hot, it can not cool down, unless you shut it off.
It depends on the cooling capacity as well. As some have shared, certain engines won't heat up. If you have an adequate coolant capacity, it won't heat up, but some smaller systems, such as those on the Japanese tractors, don't have much extra capacity.

 

[KYErik]

MHarry is right- It depends on the cooling system design as to whether no thermostat might lead to overheating. If the thermostat is regulating flow through heater hoses and if removing the thermostat then allows the waterpump to bypass the radiator and cycle coolant in and out of the engine, then yes it can lead to overheating (the radiator gets less coolant flow and gives up less heat).

A lot of websites state that you should not remove the thermostat because coolant can flow through the radiator too fast to give off heat- but the physics of heat conduction just doesn't work that way. If the fluid velocity is twice as fast, then yes, a water molecule travels through a radiator in half the time but there are twice as many water molecules moving through the radiator and transferring heat.

If you have plenty of airflow through a radiator (heat exchanger), a higher coolant flow rate will always transfer more heat from the fluid and into the air.

That said, there really isn't a reason to remove a thermostat and run the engine without it (unless it is stuck closed and the auto parts store is closed for the weekend). A lot of people remove the thermostat and it doesn't help their overheating problem because the radiator is plugged.

Removing a thermostat always causes its own problems (lower operating temps, lower oil life, higher cylinder/ring wear rates). None of my tractors had thermostats in them when I bought them, but I installed them so the engines would last longer.

 

[RobJ]

A lot of websites state that you should not remove the thermostat because coolant can flow through the radiator too fast to give off heat- but the physics of heat conduction just doesn't work that way. If the fluid velocity is twice as fast, then yes, a water molecule travels through a radiator in half the time but there are twice as many water molecules moving through the radiator and transferring heat.

Reminds me of the insurance commercial about the girl who learns everything on the internet. Met the French guy on the internet to.

But same principle with HVAC systems and heat transfer.

I know my feet have plenty of fluid in them. If I run barefoot across a hot parking lot my feet don't get as hot if I take a casual stroll. So heat is being transferred to my feet for sure. OK so the physics are probably not the same..wait...let me Google it.

J/K...

 

[Midniteoyl]

Haha..

 

[holt50]

holt50 I HAD A TRACTOR THAT I THOUGHT WAS RUNNING HOT AND CHANGED THE THERMOSTAT;COME TO FIND OUT IT WAS THE SENDING UNIT ,YOU CAN GET A PIECE OF 12 TWO COPPER WIRE AND OPEN THERM. AND PUT IN WIRE AND IT WILL HOLD IT OPEN, WON'T RUN HOT THEN ,IT TAKES A LITTLE LONGER TO WARM UP IN THE WINTER