Pour a cap full of oil in to the cylinder and do a compression test if comp. goes up its rings if it stays the same then look for burnt valves or do a poor mans leak down test. Hook up a air noozle to the air hose put it into each cylinder and see were the air comes out, radiator= head gasket,exhaust=exhaust valve, intake=intake valve,oil cap = rings. WARNING-WHEN FORCING COMPRESSED AIR INTO THE CYLINDER YOUR MONTERO COULD START. Just pull the fuel pump relay.

93 montero sr 3 inch body lift 31x11.50 super swamper ltb, 2 8inch 130 watt pro comp off road lights, 2 55w lights on the rear bumper, rear air locker, magnaflow exhaust muffler,superwinch manual hubs,15x8 black rock crawlers (steel)