Hello,

I have a 1993 Bravada 233k on the clock with the 4.3L. I was driving to work and it ran the temp gauge right into the red as soon as i reached highway speed. slowed down and got off at the next exit, before I could slow down the temp dropped back to normal. idled at the light to get to a gas station and it was fine, as soon as I gave it gas to go it started to climb again.
checked top radiator hose and it was squishy, like there was nothing in it. there is no antifreeze smell in the exhaust and it seems to run fine, temp wise, below 50 mph.

it seems like when the engine is under load it runs the temp up, at idle it's fine, but as soon as I start cruising it pushes the temp to the warning light.

just installed a new radiator, water pump, thermostat and temp sending unit. coolant level is good and there is no water in the oil and the heater core is not gurgling. I am going to try and bleed it again when I get home and so far I am leaning in the direction of a new intake gasket set.
any help is much appreciated!

 

Do a coolant pressure test, that will let you know if there is any issue with your intake gasket.

 

Fixed it.
Checked pressure and it was fine.
Turned out to be a combination of issues. First off the air was not bled properly, the person I bought it from had put the radiator in and just filled it and called it good.
Second was the fan clutch was not engaging correctly.
Bled the rest of the air, replaced the clutch and it works fine now.
Thanks for the help!