Checking the sealing plane of the cylinder head must be carried out in the following order. Remove and disassemble the cylinder head. Check flatness (warpage) sealing surface of the block head using a conventional straight edge and a flat feeler gauge (pic. 3.72).
The flatness is eliminated by grinding the mating surface of the head on CTOA, for this it is necessary to check the height of the cylinder head. The nominal height of the cylinder head is 140.0 mm, the minimum allowable, after grinding, should not be less than 139.7 mm. Under the cylinder head that has been ground, it is necessary to install a repair sealing gasket for the cylinder head, which is 0.3 mm thicker than the standard one and has the index in the marking «+0,3» (pic. 3.73).
Before installation, the cylinder head must be checked for leaks using a set of tools to seal it. Connect a compressed air source to the tool and immerse the cylinder head in a bath of water, if necessary, you can reduce the hardness of the water with detergents. Give a test pressure of 4.5 bar (kgf/cm2) and check the tightness of the cylinder head for cracks in the walls by the appearance of air bubbles.