Ok, picked this truck up the other day, wouldnt start.
Just needed TPS
The Engine was "Supposedly" rebuilt 30 000 miles ago

Now for the Problem;
When driving after approx 45 mins on highway, Temp goes to redline, (fluctuates at first, then stays)
Rad cap gets cold, Rad hoses get real hard.
Replaced T Stat and Rad cap.

I have noticed when running truck with Rad cap off, there are a lot of bubbles.
If I pinch off line coming from intake to ThrottleBody, the bubbles go away.

Do I have bad Head gaskets (or a crack) or could it be something else?

I am a Licenced Tech, but my experience is mostly with Chevs.

Thanks A Lot.

 

Try replacing the thermostat. If hoses are hard and guages are reading hot, then the thermostat may not be letting coolant past. It's a $6 or so part;a cheap start to a trouble shoot.