Originally Posted by flyboy3633

Check the radiator tanks. It sounds like you've already checked everything else. They're only plastic and more than likely one has cracked or even separated from the core. The radiator in my '99 Tahoe just cracked open. It cracked high on the driver's side right around the connection for the upper transmission line. It was a big crack too - about 3 inches long. I tried running the truck with the radiator cap half off so it wouldn't build pressure and force the fluid out, but the water would drip out at atmospheric pressure. I ended up getting a used four-core off a guy on Craig's List for $50.