Checking Hardness

NOTE:
^ Loss of coolant or faults in the cooling circuit or at the cylinder head gasket can result in overheating and thus in distortion and change in the microstructure of the cylinder head.
^ Refacing the cylinder head then only produces a tight seal between cylinder head/cylinder head gasket/crankcase if a certain minimum hardness is achieved.

TESTING PROCEDURE
1. Smooth the surfaces to be inspected in one direction with a fine abrasive stroke.
2. Inspect hardness at two points (arrows) in the areas of the blowby traces of the cylinder head gasket.
- If the hardness is not achieved, replace the cylinder head.

CYLINDER HEAD HARDNESS SPECIFICATIONS
Hardness of cylinder head contact surface in area of sealing bead of cylinder head gasket: >70