Cylinder Head Assembly: Service and Repair: General Procedures
Cylinder Head Distortion1. NOTE: Make sure all cylinder head surfaces are clear of any gasket material, RTV, oil, and coolant. The cylinder head surface must be clean and dry before running a flatness check.
NOTE: Use a straightedge that is calibrated by the manufacturer to be flat with 0.0002 inch (0.005 mm) per running foot length. For example, if the straightedge is 24 inches (61 cm) long, the machined edge must be flat with 0.0004 inch (0.010 mm) from end to end.
Using a straightedge and a feeler gauge, inspect the cylinder head for flatness in the sequence shown. If the cylinder head is distorted, install a new cylinder head.