1981/11/13 Caterpillar

3406, 3408 Truck Engines

Some of the Service Manual information about inside diameters of valve guides for the above engines is not complete. The correct dimensions are:

... Valve guide inside diameter (installed, new) - .3735± .0010 in. (9.487± 0.025 mm).

... Maximum diameter for a used valve guide (wear limit)- .3758 in. (9.545 mm).

In the Service Manuals, the inside diameter for new valve guides is shown in the "Specifications" section and in the "Disassembly and Assembly " section. This dimension is shown correctly.

The maximum diameter for a used valve guide (wear limit) is normally shown in the "Disassembly and Assembly" section, but is not shown in two Service Manuals. Add the wear limit dimension of .3758 in. (9.545 mm) to the Service Manuals for 3406 Truck Engines, Form SEBR0512, and 3408 Truck Engines, Form SEBR0501.