My 97 was leaking from that connection and the dealer replaced the connector and hose under my GMPP Warranty at about 65k miles. It's called a "Snap-In" connector used to make the assembly line go faster. If your truck starts to heat up then gets too hot real fast or the guage doesn't move at all, then your T-stat is bad and check for steam out of the exhaust or "stuff" in the oil and that means your head gasket is gone. Make sure to have the heads saved if you replace the gaskets.
And if it gets hot again turn the heat to max and the blower on high, the heater core is like a miny radiator. But you are low on fluid that won't help!
