Elevate front of machine 10inches or so, open bleeder screw on top thermostat housing on top of engine and fill radiator until solid stream comes out bleeder this is with the engine off. Then start engine and allow to run for awhile then open bleeder several times while keeping radiator full plus the overflow bottle to the full line. Then take it for a small ride or let idle and bleed again. Hopefully that gets it. DOES YOUR WATERPUMP OPERATE?