you can check the head gasket with air pressure. you need a hose adapter to the spark plug hole (i use the hose from my compression checker)

cycle the cylinder to TDC of the compression stroke, add compressed air (not too high or the engine will turn over and open the valves) look for bubbles in the radiator, air escaping sound from the oil cap is bad rings. you can also check for bad valves... air escaping sound in the intake, or exhaust.

repeat for each cylinder.