92 es 300... Only heats up on an incline...otherwise runs perf, needle stays about half way..But any incline where u have to gas it up a hill temp goes up quick, soon as crest the hill and car isn't under a major load temp goes back to normal and no issues at all..Any Ideas??? im stumped!!!

 

First and easiest thing to check is if the radiator fans come on. Next would be the thermostat. A defective radiator cap could also cause this.

All of the above assume of course that your coolant level is proper.

Phil

 

Fan comes on.... thermo sounds to be working or would overheat always??i think!!! I will replace caps asap... also forgot to mention we just bought this pile of crap and notices the coolant tank is gone...they linked the the overflow hose from rad to the overflow at the other cap by the engine..

 

Thats cant be right get a reserve coolant tank from any junk yard its not expensive and look around the engine block and check if something else is missing/modified.