1991 Mazda Truck Over Heating

well its either going to be a clogged radiator or a bad head gasket. if you can get access to a infrared thermometer you can go across the radiator and see if any of the cooling rows are not flowing. also there is a kit you can buy that tests the coolant to tell if the head gasket is blown but its a little expensive.

Thank you for your reply mastertechtim.

I kept working on the problem and another weird thing happened I by passed the heater core and ran the truck. The truck started to overheat like normal in about 45 minutes however this time it did not go up all the way rather it came back down to medium. However it started to go up and down. I ran it for about 1.5 hours this time, so I turned it off. An hour later I took the truck out and it overheated and this time it did not com back down. When I got home and turned the truck off I could hear the coolant boiling in the radiator.

Another question is people say that smoke and drops of water out the tail pipe is a sign of the gasket gone. Is there supposed to be none what so ever even if the truck was cold?

Also do you get paid for this? Should I make a donation?

yes we get paid for this. this sight works off of donations. the moderators get a very small amount of money for answering the questions because very few people donate, i get paid whether you donate or not, it just helps us out. on the smoke thing. if you start your truck up cold and it runs a little shakey and blows a little smoke. that is a tell tale the head gasket is blown. bottom line is i think your going to find that the problem is the head gasket.