running hot b2200, In winter!

[RaulLince]

Just put rebuilt head on my truck new thermostat, new coolant. But My truck fluctuates in tempature (all in the normal range) under a load going up hills on the interstate. I'm at a loss. New radiator cap, and the motherfucker keeps heating up. At idle it does not do it but at speed( 60 70 mph) temp guage starts going up and down never below middle. Does your truck run in the lower 1/4 of the guage or in the middle? This is my first long drive since the new head so i am confused. Any advice out there. Raul

[Mikey350D]

My truck is doing same: replaced fan clutch, thermostat & water pump and truck still heats up at highway speeds. Suspect head bad.
Rad pressure check was good.
Performed block check (combustion gas in rad) when motor was cool.
Pulled head off today: cracks between plug holes and valves.
You need to have your head work done by a quality shop; who can (heat) straigten, line bore and not over-shave (or shim).
I replaced original b22 head with b20 head to get rid of hydra-lifters.

[markbaham]

I had a similar issue. Mine only overheated when I went above 50mph. My problem was simple. My truck sat for about 2 months before I fixed it. In that time, the radiator got clogged up. It would not overheat while idling for an hour, but as soon as I drove it down the road it went hot.

[brownt]

I had the same problem, I upgraded my thermostat to the best grade NAPA had & my overheating on the highway stopped.