Notes On Diesel Engines (15.20/63)

A. COMMON RAIL LEAK OIL LINE

MODEL 164, 164X, 211, 251 with ENGINE 642 

When servicing the CDI system with piezo injectors, do not intentionally restrict the Injector leak-off fuel lines in any manner i.e. kink, clamp, or cap them off. Doing so will cause damage to the actuator sleeve resulting in injector failure.

B. NOTES ON CERAMIC GLOW PLUGS

MODEL 164, 164X, 211, 251 with ENGINE 642 

In order to prevent damage to the engine, it is important to observe the following information concerning ceramic glow plugs:

• Ceramic glow plugs are very sensitive to impact shocks. Impact shocks cause invisible damage (hairline cracks) to the ceramic element and lead to engine damage.
• If the ceramic glow plugs have been dropped, it is essential that they be replaced.
• Only use ceramic glow plugs from sealed, original packing.
• It is not possible to check the ceramic glow pin for mechanical damage (e.g. hairline cracks).

C. TURBID FUEL AFTER CHECKING INJECTOR LEAK OIL VOLUME

MODEL 211 with ENGINE 648 

After the injector leak oil volume has been checked using the graduated tubes, the fuel in the graduated tubes may exhibit varying degrees of turbidity (rust-colored). This is not an indication that the injector is defective. The turbidity is caused by contamination (corrosion deposits) at the leak oil outlet of the injectors.

Fig 1: Checking Injector Leak Oil Volume Using Graduated Tubes