1992 Pontiac Transport coolent leak

If this is a 3100 or 3400, then it is probably a defective intake gasket. GM went cheap and used a plastic encased gasket that fails often. U can usually see a small stream or remnants of coolant behind the power streering pump nest to the intake manifold/uppr plenum. Otherwise, check the coolant bypass tube behind the waterpump, they like to rust and fail also.