Thermostat car overheats

I would highly recommend to change the thermostat. I have a Toyota Dolphin RV had similar symptoms. Thermostat was opening but not fully opening. Change thermostat runs at normal temperature now.

You did not mention the Thermostat which controls the temperature of the engine. Did you mean the Thermostat when you said temp sensor? If not, then change the thermostat.

my guess is you think the dash guage dont lie?
define overheat.
1: pyro IR gun shoot thermostat house it read 250F?
2: steam rising from hood.
3: green coolant every where.
just a hint, and we can proceed.

define overheats, what made you think that........??????????

replace the thermostat housing and use hi temp gasket silicone.

Thermostat may be installed upside down...this can cause overheat.
To test your engine...if you don't think thermostat is faulty, remove the thermostat.
This is sometimes called "running cold"...and it should not overheat. If it does, you have bigger problem than thermostat.
You can test thermostat too by placing it in hot water thats not quite boiling and see if its opening properly.

Hope this helps...

It could definitely be the thermostat. It is a cheap part to replace. If the car overheats while running down the road (not stop and go traffic), then it is almost certainly the thermostat.

We just did the same car with the same prob. The block was cracked and was pressurizing the cooling system causing the thermostat not to open. Remove your thermostat and run the car if it doesn't overheat you need a motor. Ours didn't show any hydrocarbons in the coolant either, so try the simple

Only 2 parts remaining are the thermostat and waterpump. Always start with the thermostat when diagnosing an overheating problem. If the car is overheating constantly under all conditions and coolant is backing up into the reservoir, it's very likely to be the thermostat. If it only overheats at low speed or idling, it's more likely the waterpump.

Are you putting the thermostat in correctly? It it will not work backwards.

And to confirm that there isn't a different problem, take the thermostat out all together and see if it overheats.

Engine not fully warming up is not usually caused by the thermostat. Stats usually fail closed, not open.

You will want to check the water temperature sending unit or gauge after verify the water temperature with an external calibrated thermometer. You can attach and insulate the external thermometer to the housing where thermostat is located.


Reply back what you figure out. I will be happy to help you further.

CHECK SOME BASIC PARTS, THE THERMOSTAT AND YOUR WATER PUMP, THE THERMOSTAT MAY BE THE WRONG DEGREES OR THE WATER PUMP IS GETTING A TIRED YOU JUST HAVE TO FIGUERE OUT WHICH ONE. IS THE PROBLEM...
CHEERS..