Engine problems
 

So after my radiator blew, I am starting to notice some odd engine behavior. The oil pressure seems to be low, the temp gauges wanders from normal position to almost redline, a rattle comes from the engine when I rev it and then let off. Any ideas? Do I need a new engine?

The idle also changes at almost every stoplight, ranging from 1-2k rpms

Anyone?

Did you purge the air from the system when you replaced the radiator? There's a thread somewhere on the board about it. As for the rattling, may be the timing chain. Not sure if your year has the chain or belt. Good luck!

why did the radiator "blow"? How hot did the truck get when this happened?

There was a leak. I used some repair stuff, it seemed to be working then while driving I see it start to smoke, pull over, pop the hood and coolant is all over the engine bay.

So the engine never overheated?

didn't seem too. With out any coolant, the temp sender could give an accurate reading, but the temp never went into the red.

"Hunting" for an idle speed and a wandering temp. gauge are a good indication of an air bubble in the system. Give it a good burping.

Rattling sounds coming off of a speed run could suggest a loose heat shield. Seeing that the engine did NOT overheat check the simple stuff, first.