ELBOW-EXHAUST 2138169 - Caterpillar

The new high pressure turbocharger group and major parts are all serviceable and can be ordered through the Caterpillar part system. The new cast iron compressor housing can not be used with the former cartridge groups.
This is because the new cast iron compressor housing bolts to the cartridge group, while the former compressor housing clamps on the former cartridge group.
To provide clearance for the new compressor housing, different adapters are needed for the turbocharger oil and cooling lines. Due to the need for additional clearance, bolts with low profile heads should be used to attach the new compressor housing to the new cartridge group. Chart C lists the parts needed to install a new compressor housing and new cartridge group.
Some early 138-2292 Turbocharger Groups were shipped with the 125-5325 Bolts attaching the cast iron compressor housing to the cartridge. These bolts should be replaced with 147-3737 Bolts prior to installation of the turbocharger group on the engine.These improvements are effective with Remanufactured 3516 Electronic Unit Injected (7CL394, 399 - Up) Engine for use in 793B Off-Highway Trucks.
793C Off-Highway Trucks
Charts D and E provide lists of the improved serviceable parts that are adaptable to the high pressure turbochargers in the 121-5802 Turbocharger Group.
Both the new 138-2305 and former 134-0386 Turbocharger Groups include the new style single piece bonded design thrust bearing. This prevents looseness with the back plate.These improvements are effective with the 3516B (7TR) Engines in 793C (4AR155) Off-Highway Trucks.