Alright for the results thus far. Went ahead and looked around for a leak down tester to borrow/rent without any luck. Guy at Schucks was nice enough to check in with the Napa down the street and found option #2, a block tester kit. Kinda freaked out initally when I ran the truck up to operating temp like the instructions said to and the uncapped radiator belched out a good amount of antifreeze. Called a local shop who recommended I try again and sure enough no geyser, just a nice flow of fluid into the motor. Placed the nifty tester on the radiator and pulled a ton of air through the tester fluid in the chamber. No change whatsoever!! Ran it again with new test fluid just to verify and again no color change so I'm feeling pretty good that the HG is intact. <img src="/forums/images/graemlins/smile.gif" alt="" /> I went ahead and changed the antifreeze, oil and plugs and ran her around the block with no temp issues, no power loss or white smoke(none noted to begin with). Here's the thing...there was still a tiny bit of build-up on the cap after the oil change, just like if the HG was blown. Outside temps have come up and I can see that I'm not blowin' white smoke. So I've decided that the buildup I'm seeing is either frosting when the temp drops at night or it's being caused by a oil additive I dropped in a short while back. I'm figuring that some of it was left in the top of the motor, even after the oil change and hadn't been consumed yet. Anyone noticed that before with an oil additive? It was added to help seal up a leaking oil gasket, brand name, just can't remember it. Truck ran strong all the way into work this morning and no build-up was noted on the inside of the oil cap and the dipstick looks good. <img src="/forums/images/graemlins/kewl.gif" alt="" /> Still haven't figured why the radiator overflow was empty, that's the next challenge. <img src="/forums/images/graemlins/confused.gif" alt="" /> Thanks to all for the information and help. <img src="/forums/images/graemlins/patriot.gif" alt="" />