PUMP & MTG GP-HYDRAULIC 1415866 - Caterpillar

3100, 3200 and 3400 Engines with Direct Injection Fuel SystemsRemove the fuel injection nozzles from the above engines before the bottom surface of the cylinder head is cleaned. This will prevent possible damage to the orifices in the tip of the fuel injection nozzle.
Direct injection fuel nozzles extend beyond the bottom surface of the cylinder head. The nozzles can be damaged by the tools used to clean the cylinder head and/or when the cylinder head bottom surface is moved across a work bench.
Damaged fuel injection nozzles will not let the correct amount of fuel flow into the cylinders and poor performance and damage to the engine will be the result.