Valve Guide Identification Measurement: Procedure:

With cylinder head removed from engine and valve removed from guide, thoroughly clean the valve guide using a drill driven guide brush and solvent.
NOTE: The Go (Green) end of the gauge should go through the entire length of the guide with light and uniform pressure. Use of excessive force will result in tool damage.
Insert the Go (Green) end of the appropriate gauge (P/N J43120 or J43481) into the guide from either the combustion chamber side or the camshaft side:
- If the gauge passes through the gauge with light and uniform pressure, proceed to step 3.
- If the gauge will not pass through the guide with light and uniform force, clean the guide again as in step 1 and repeat the guide measurement. If the gauge still will not pass through the guide with light and uniform pressure, refer to the valve guide repair and/or replacement procedures in this section.
NOTE: The No-Go (Red) end of the gauge should not enter either end of the guide. Use of excessive force will result in tool damage.
Attempt to insert the No-Go (Red) end of the gauge into both ends of the valve guide:
- If the gauge does NOT enter either end of the gauge, the guide is within the correct specifications for diameter, straightness, and roundness.
- If the gauge enters wither end of the guide, the guide is oversized beyond specifications.