Alright,
I was on my way to work this morning and it has happened several times before. It seems that after my car has been going for about 3-5 miles all the sudden the temperature gauge will rise all the way up and the light will come on. Usually I don't realize it right away. I will look down and get ready to pull over and the thing will go back down again. It will return to just below 50% or so. Probably sticking around 40%. This happened 3 times on my way to work this morning, even though 1 time I did pull over, let it sit for a couple of minutes. I popped the hood and couldn't smell anything, there was a tiny tiny tiny amount of steam, but I think that might be because it was a cold morning and all. I looked in my water resivoir and it looked alright, probably could use a little fill up. Could there be a blockage in the system? Small leak? Vaccuum problem? Other?

Thanks in advance for the help.

John

 

It's most probably a stuck thermostat, or you have an air bubble in your cooling system. If you aren't afraid of a little steam, next time it overheats pull over and shut your truck off. Then get a thick shop rag or something to put over the reservoir cap and start to ease the cap off to let any excess air out of the cooling system.

I say to ease it off because if the coolant starts to shoot out the top of the reservoir, you can quickly tighten it back down and it'll stop it before it comes out and burns the hell out of you. If it starts to do that, just tighten it back up and let it sit a few minutes and try it again.

This is dangerous, so be careful and use caution! If you're not comfortable trying this, ask someone with some experience with vehicles, or just take it to a mechanic.

 

I agree;thermostat.Other things to check are the fan clutch,look for leaks coming from the water pump,or a partially clogged radiator.