I just bought an lly. 2005 Chevrolet 2500hd. When it was at the used car dealership it was leaking out of the water pump. They replaced the water pump and its hose. So I bought it AS IS for tax savings and now its leaking out of the coolant overflow cap tube. It only drops about two inches in the reservoir. Its not enough to trip any alarms but I'm pretty sure its not supposed to be doing that. I've been told if it was head gaskets the upper rad hose would be rock hard when the engine has cooled and sat for a while. Its soft. I have heat and my gauges show no signs of overheating. I bought it from these Ukrainian Russian dealers in NE Philadelphia. They get their trucks totaled or damaged and swap parts from other damaged trucks. Could it be that the reservoir is larger than the original? I dont even know if that was even ever replaced. If it was the cap, would it stop dumping coolant two inches down? It seems to hold pressure in the reservoir cause when the water pump was leaking the salesman unscrewed the cap after a test drive and the coolant came shooting up and out like a volcano sending the cap across the parking lot. If the thermostats were stuck would I still have heat?