Areas of the cooling system to check for leaks
Check the core plugs in the side of the cylinder block. Check all hose connections for tightness, but ensure that the clips are not cutting into the
rubber. Look along the hose for cracks, especially at points where the hose is flexed by engine movement.
Inspect the radiator seams for splits, also the catch tank and its pipe. Watch for leaks at the water-pump bearings and from the pump gasket.
Check the thermostat housing for cracks, and the housing gasket for leaks.