Radiator Thermostat?

I live in Scottsdale Arizona and I have a 1996 Jeep Grand Cherokee V8 and It has been overheating I have changed the water pump, radiator, all the hoses and the thermastat but it still overheats. does anyone have any ideas of what might be wrong? Also I was told that I dont need the radiator thermostat because it doesnt freeze here, is this true?
Radiator Thermostat?
if it has an electric cooling fan, check that out, if you have a conventional engine driven fan, check the fan clutch.



As far as the thermostat, it serves two functions, it helps the engine reach operating temperatur sooner, and regulates coolant flow through the radiator. A normally operating thermostat will slow the flow of coolant through the radiator allowing the cooling fan or vehicle speed to provide more cooling time for the coolant in the radiator. (which, by the way, contradicts most peoples common perception of a thermostat's proper function) I also suggest drilling a 1/8 inch hole in the flat plate of the new thermostat prior to installation, this does not hurt the function, and allows air to escape from the engine block when filling your system, as opposed to trapping the air under the thermostat. A thermostat will not open in hot air, only in the presence of a hot liquid.
Radiator Thermostat?
If your engine cooling fan is electric, make sure it is operating properly. if not you may have issues with the head gaskets.
As far as the overheating goes, have you noticed if you were leaking coolant anywhere? that may cause it to overheat.
I would guess, bad cooling fan, or blocked radiator.



You need the thermostat because it allows the engine to reach operating temperature quickly. The engine does not operate properly untill it has reached a certain temperature.
cooling fan would be next check and to see if the radiator is just plugged up. If the fluid can't flow through the radiator it can't cool.

(I assume you have cleaned the radiator? between the radiator and A/C condenser coil?)

Did you install the thermostat in the correct direction??

did you check the new one to see if it is working?



yes.. you should have it installed
Does it overheat while you are driving on the freeway, or only when sitting still or traveling slowly? If it is fine until you come to a stop, there is likely a problem with your cooling fan, and it is not pulling air through the radiator to cool the fluids. Check that first. simple test would be to start it in the driveway and let it heat up. if you hit 210 on the temp gauge and your fan is not on, then there is your problem. (they typically turn on around 180-190) check the relay and the fuse if it has one. other quick test is that almost all fans are tied into the A/C, so that when you turn the a/C on it automatically kicks on the cooling fan on the radiator.
If it overheats, let it sit on the side of the road for about 20-30 minutes, open the hood to release captured engine compartment heat, then remove the radiator cap (caution). Don't do it until you are sure that the engine has cooled down, and are sure that the cap wont release the large amounts of pressure that it builds up, therefore allowing the antifreeze, and water to splash out and possibly burn you. Heed my warning, as i am not responsible for anything that happens to you are anyone around you if you do what i above described.





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Try backflushing your whole system, I also agree with checking your fan. And you do not have to have a thermostat but you will not be able to have any heat. You can always run without one for now and install it after summer if you want to. It does allow your engine to warm up faster, but if that is not a concern to you I wouldn't worry about it. I run without one in my Bronco.
You need a thermostat to keep engine running at correct temp. If it doesn't get hot on hyway but does when you set still then cooling fan not working properly.