Section 2 - Cylinder Head - Group 02 Cylinder Head - Vacuum Test Valve Seating (2-09) M11 Page 2-31 Remove the test equipment. Use compressed air to dry the cylinder head. Assemble the cylinder head. Refer to Cylinder Head - Rebuild - Assembly (2-02) Cylinder Head - Vacuum Test Valve Seating (2-09) Use valve vacuum tester, Part No. ST-1257, to inspect the seal between the valve and the valve seat. NOTE: The valve vacuum tester is not recommended for use on used heads. Refer to Procedure 7-07 in the M11 Trouble- shooting and Repair Manual, Bulletin No. 3666074, for the recommended procedure to check used heads. NOTE: The valve vacuum tester can be used to test all Cummins engine models.
The seal ring, Part No. ST-1257- 35, and vacuum cup, Part No. 3376100, are used on the M11 cylinder heads. Install the seal ring and vacuum cup to the vacuum line (hose). The valves and valve seats must be clean and dry when vacuum testing. Cover the valve with the cup and seal. NOTE: The seal must make a tight contact on the cylinder head around the valve.