If my car overheats do I need a new thermostat?

Answer 1

yes

put some money into it

Better info: If your car overheats then there is a problem in the cooling system which can be one of several problems. most are easy check and/or fix yourself.

While the engine is completely cool...do the following

1. As always first check the coolant level in the radiator and/or the reservoir

and make sure it is filled to the proper level with coolant.. it must be filled with engine coolant and not JUST PLAIN WATER (a 50/50 mix of anti-freeze and water is acceptable unless you are operating in extreemly cold conditions)

Inspect all of the radiator and heater hoses for any damage,check all the hose clamps and make sure they are all properly tight.....

(for this step you will need a coolant thermometer or cooking thermometer that can reach a temp of atleast 350*F)

2.After doing the above If your vehicle has a cap on the radiator then remove the cap so that you can see the engine coolant in the radiator..(if your vehicle has only a reservoir and no cap on the radiator itself then it is a sealed system so skip to step 3)...Now if you can clearly see the engine coolant by looking into the radiator then start the vehicle and allow it to run at idle speed,stand and watch the coolant it should move around fairly slowy because the thermostat is supose to be closed when the engine is cold....have someone monitor the temperature gauge or light in the vehicle while you monitor the engine coolant temp with the thermometer by carefully placing it into the radiator.As the engine warms up to operating temp the coolant flow in the radiator should increase in the direction of the upper radiator hose,monitor the temp as it does,the thermostat should be fully open between 125-155*F and you should have a visable fast flow towards the upper radiator hose...

If the flow does not increase and remains slow and the temp reaches 165*F shut down the engine immediately,this would indicate that the thermostat is stuck closed..((Also note that if you see a fast flow towards the upper radiator hose when you first start the engine cold then that may indicate that the thermostat is stuck fully open,which can cause cooling problems,especially in hot weather...)))

(after the engine cools down drain 50% of the engine coolant into a secure container and then change out the thermostat,and refill and test as above )

3. If you have replaced the thermostat and re-tested and your engine is still overheating then this could indicate one or both of two problems.

The first could be that the vehicles coolant(water) pump is not operating properlyand moving the collant as fast as it should..

The second is that the vehicles radiator core could be bad and needs replaced,radiators have small passages inside that can over time become clogged/corroded and coolant will still move through parts of the radiator but it will not cool properly...Since in most cases the coolant(water)pump is cheaper to purchase than a new radiator you should start with the pump first..

If you replace the pump and the engine still overheats then replace the radiator or take it and have it repaired...

Also note that if your vehicle has an automatic transmission the radiator also cools the Transmission Fluid,so if there are any transmission issues they could affect the cooling system as well,check the transmission fluid to make sure it is the proper color,it should be a nice red color,if the fluid is very dark or almost black then the fluid is getting to hot and you may have a transmission pump issue...