Opinions for engine temp issue.

[cmhaah06]

My truck recently started having cooling issues. When driving the truck it gets up to normal temp at a normal pace. The needle in the temp gauge will continue to move towards the A-L, sometimes a little higher. The truck then cools down and will run around O-R in the temp gauge. Is this more likely to be a t-stat or possibly rad cap? Or both? The truck never over heats, yet. The truck will cool to normal on it's own but if I rev it up a bit that also brings the temp down. Any suggestions?

 

[walterd140]

I would check the fluid level. Could have air trapped in the system. Make sure the reservoir is filled to it's level as well.

 

[92exp4x4]

Most likely you have an air bubble. My limited started doing this same thing after the heater bypass valve (94s only) exploded, belching coolant everywhere. I replaced the valve and refilled the system and afterwards the gauge would jump around like yours, but only at highway speeds. I never noticed it moving much before this. I have added a little coolant since, so I think its just working a bubble out.

I would try jacking the drivers side of the truck up as high as you can get it, and fill the radiator that way. This will make the rad neck the high point of the sytem and the place where the air should go.