My truck has started to overheat. Right after I start it it heats all the way up to the danger level. If I drive it overheated for about 3min it cools right back down to normal temperature and will stay at the normal temperature as long as I am driving at a steady pace. However if I stop, like at a stoplight, the temperature will quickly rise again. I'm at a loss as to what this could be?

 

It is a 1999 Ford Ranger.

 

Have you checked the amount of coolant you have?

 

Yea check the coolant or the fan that it works properly.

 

Could be thermostat stuck too

 

Fan clutch is my guess

 

i have a lot of trouble with mine doing this (once a year at least) and i normally drain the radiator and flush it out with a hose and refill and that usaully fixes it for a while. I've also had to replace the thermostat once tho.

 

it sounds like you either have a blown head gasket or your thermostat is sticking

 

your radiator core is plugged with deposits

it is passing just enough coolant to cool it at speed

 

My guess is the thermostat. Mine didn't heat at all. So I put some cardboard in front of the radiator and I got some heat. I did this to check if the gauge was working. Removed the thermostat and it was stuck open. I just sanded all the rust from it and it has worked just fine. And that was a year ago. Ever since, I've had minus 0°C and over 40°C.