Hopefully someone can help me out. I have a 2000 Silverado with the 5.3L engine. Recently, I have been losing coolant at a slow rate. I have had the cooling system pressure tested by a dealer and an independent mechanic and both say that there is not a pressure leak in the system. I have checked the oil and I do not see any indication of antifreeze in the oil, so I do not suspect a head gasket problem. Also, there is no visible signs of coolant leaking from the system (I see no coolant on the ground under the car and the engine compartment does not smell of coolant). So, if the pressure is good and the head gasket appears not to be the problem, where is the coolant going? I have changed the radiator cap on the surge tank, but this did not appear to help. Has anyone else seen a problem like this? I am going crazy (not to mention spending a lot of money doing pressure tests!) with this problem. Anything will heip. Thanks!