Fixing the thermostat is a very easy repair important one. It is better to run without a thermostat than with a faulty one. A thermostat that sticks closed will cause issues similar to what you describe. Replace it, check for leaks on the entire cooling system, and make sure you get all the air out of the system. Monitor the repair by checking the coolant level rigorously.

A thermostat stuck open would be similar to not having one in and it would not allow the coolant to reach a very hot temperature and thus would poorly fill your requests for heat.

Answered by Bruce Hunt (expert)
3,798 answers provided

if your engine immediately begins to overheat, the thermostat is probably stuck closed and coolant is not flowing through the engine.This mean the coolant will begain to boil after about 5 minutes of operation.The increase in coolant pressure pushes coolant out of the overflow or like you said(the side hose for the raidiator popped off).

check your thermostat before buying a new one because it could be something causing overheating problem
- remove it from it the engine
- attach it to a peace of wire
-suspend it in a pot of water.(do not let it rest on the bottom of the water, but allow the bottom of the thermostat to touch the bottom of the water)
-place a high -temperature thermometer in the water
-heat the water and observe the thermostat to see when it begins to open
-if it does not open at the rated temperaturethen you can replace it .

good luck

Answered by mathiaso
5 questions asked