I have a 92 100 that shows the temp guage and overheating warning light with the temp guage readingat about3/4. The guageis all over the place. The thermostat wastested andchecked out fine. The coolant temp sensor was just replaced todaywith the updated three wire version. What else could it be? The water pump, rad blockage? HELP!!!

 

run the engine and leave the coolant cap off to get rid of all the air ( there is obviously an air lock in the system ) water pump is another area and will show if no circulation of the coolant in the expansion bottle

 

Thanks, I'll give it a try. The temp has slowly begun to climb in the last year or so but I didn't have the cahs to maintain it until now. When I first bought it three years ago the temp never reached half way. Also what would cause the car to wander or follow the grooves in the road, like from truck weight? The control arms were replaced and I know the cv's are cooked. It has BBS SX wheels 18"x225 Bf Goodrich scortchers. The tires have radial grooves on the outside of the tire and a small portion of regular tread on the inside.