Typically if your truck is running hot and there is no leak or noise.

Is it most commonly the thermostat?

 

Or low on coolant

 

Or dirty fins on radiator/other coolers up front, or fan clutch not engaging, or collapsing hose, or water pump on the way out, or.....There are quite a few variables on cooling systems.

How long does it take to overheat? Under what conditions does it happen?

 

at 45mph its fine, as soon as I get on freeway, get up to 70-75 within a mile starts overheating..... 85-90 degrees out

 

sounds like your water pump. maybe even a Rad.

 

Doesn't the water pump leak or make noise when its going???

 

It wouldn't leak but it should make some pumping straining noises. If you have over 130k that's you best bet. Especially if you have no signs of a leak.

Wait for the truck to cool down one day and check the coolant level in the rad. If its low fill er up and run it for a few days, check it again.

 

Just replaced thermostat and it stopped but we will see.....my truck only has 84000 so I am hoping it was just the thermostat, when I have some time I think I will just replace water pump to be sure.

Thanks everyone for the help.

 

If the water pump is on its way to lunch, it will start to weep coolant.

Could be a failing/failed waterpump.

Could be a plugged/collapsed radiator.

Clogged/collapsed radiator hose

Failing/failed thermostat

Failing/failed temp sending unit

Failing/Failed fan clutch

Low coolant

Trashed serpentine belt that is just roasting everything and not turning the waterpump/fan clutch.


Or just a plain case of too much **** like mud and leaves stuck in the radiator