not being smart but if you removed the thermostat not all but some eng's will overheat because without it the water flows to quick through the rad. i don't know what eng you have but is thermostat off set type if it is must be fitted correctly [usually valve oppeisit rad hose]for flow other wise it restricts the flow out of the eng. to preasure flush eng you use a special multi sized rubber fitting that has hose &air fittings attached to it, it fit's inside your rad hoses but must be done in the right direction with thermostate out no air preasure greather than 18-21 psi app..VERY DANGERIOUS EXP NEEDED YOU CAN F RAD OR HURT YOUR SELF ...@@???.dose's the rad get preasure in it before it get's warmed up if it dose's i'd say head gasket don't check to soon though it mite only be slight leak,BETWEEN ALL OF US WE SHOULD BE ABLE TO SORT IT OUT . BY FOR NOW