Gauge Reads Hot, Pressure Cap Vents to Reserve Tank

1. Coolant level low in radiator and coolant reserve tank.
^ Fill cooling system and vent trapped air.
^ Inspect for leaks. Repair as necessary.
^ Ensure that pressure cap is completely shut and seals.
^ If level is low in radiator but normal in the reserve tank, check the filler cap to reserve bottle connection and pressure cap seal.

2. Test coolant freeze point.
^ Adjust coolant to 50/50 mix of anti-freeze and water.

3. Ensure coolant is flowing through system.
^ With the coolant level low and the thermostat open, check for coolant flow through the radiator at the filler neck.
^ If a metal cracking sound is heard, inspect for core sand restricting coolant flow through the water jacket and/or a faulty cylinder head casting.

4. Thermostat stuck in the closed position (prevalent in cold ambient temperatures).
^ Replace thermostat if found to be stuck in closed position.

5. Cylinder head gasket leak.
^ Inspect for leaking cylinder head gasket with a commercially available Block Leak Tester.