Overheating on Interstate
 

1996 Vortex V6 4 Wheel Drive Blazer

The temp. is fine when I am idling or driving in town. When I get on the gas on the interstate it starts to overheat. So as long as I don't get on the gas I am fine. I already changed the thermostat and radiator cap. And I had the radiator flushed. What do you think it can be? I need some help.

Thanks

I really wish I could help you out, I'm having the same problem, posted it here and never got a answer.

I have replace the rad, both hoses, the theromstat, the rad cap, but this time and it might seem strange but, When I replace the Rad cap (16lb) I also added a can of Seafoam to the crankcase and it appears to be running cooler. I drove down the interstate on a test drive for about 15 miles and it didn't even reach 210 and I live in AZ where it gets hot, hot here.

Now was it the Cap or the Seafoam or both? But so far so good.

Ever think about replacing the water pump while you replaced the radiator and thermostat? You should. You might have air in your system. What you should do, since it is 13 years old, you should pull the clutch fan. Take out the water pump, and flush the engine. Then put a new water pump on and gaskets. And make sure you dont get air in your system. That should solve your issues.

So you don't think I should try the bottom radiator hose?

I would have replace the water pump "IF" I thought it needed to be replace, was not leaking, no movement as in looseness and the fan clutch appeared at that time to be alright. My radiator was leaking so I replace that and the hoses and the thermostat.
Everything ran well for about 6 months, then I notice the heat building up again on the freeway. So again I check everything out and replace the one I haven't done and that was the cap (it was orginal) and dump a can of seafoam in the crank. So far again everything is alright, when the water pump or fan go out and if I keep the truck for very much longer I will replace the items as needed.
The thermostat is one of those newer type that are made to release any air that might build up, but, I purge the system anyhow just to be safe.
Just for your info.