Valve Guide Inner Diameter

NOTE: Refer to ENGINE MECHANICAL - 3.5L or ENGINE MECHANICAL - 3.5L-GTDI for the specification.

NOTE: Valve guides tend to wear in an hourglass pattern. The ball gauge can be inserted into the combustion chamber side of the valve guide, if necessary.

Fig 1: Locating Inside Diameter Of Valve Guides

Courtesy of FORD MOTOR CO.

Use a ball gauge to determine the inside diameter of the valve guides in 2 directions at the top, middle and bottom of the valve guide.
Measure the ball gauge with a micrometer.

Fig 2: Measuring Ball Gauge Using Micrometer
Courtesy of FORD MOTOR CO.
If the valve guide is not within specifications, install a new cylinder head assembly.