1992/11/30 Caterpillar

Left Handed Threads In Compressor Nut On Some Caterpillar Turbochargers{1077,1053,1052}

Usage:

Caterpillar Engines Equipped With A Turbocharger

Some new turbocharger shaft and wheel assemblies use left handed threads to retain the compressor wheel on the shaft. The left handed threads can better resist the higher shaft torques of some newer engine ratings. The left hand threads can improve turbocharger reliability in severe service applications.

The illustration show both left (A) and right (B) hand threaded compressor wheel retaining nuts. Note the notches in the edges of the hex surfaces on the left hand threaded nut.

NOTE: Assembly procedures (thread preparation and torque) for left hand threaded nuts remain the same as those listed in the Service Manual Specification modules for right handed threads.

NOTE: It is very important to make turbocharger repairs immediately if a bearing system failure should occur. Timely repairs will help decrease the possibility of pressurized engine oil from getting into the intake or exhaust systems. Engine oil leaks into the intake or exhaust system can result in serious engine damage.

Compressor Wheel Retaining Nuts. Left Hand Threads (A). Right Hand Threads (B).

Caterpillar Information System:

1992/11/30 New Oil Pump Used As Service Replacement{3310}

1992/11/30 New Unit Injector Sleeve Used In Cylinder Head Groups{1125}

1992/11/30 New Cylinder Head Gasket Used{1124}

1992/11/30 Reporting Incidents{0337}

1992/11/23 Oil Filter Group Improved{1318}

1992/11/23 Be Sure To Use Correct Cup Plugs On 0R2077, 0R2554, And 0R3258 Remanufactured Short Blocks{1200,1201}

1992/11/23 New Service Seal Used In Altronic III Magnetos{1552}

1992/11/23 Procedure For Seating The Ball In The Fuel Return 4L8546 Check Valve{1274}

1992/11/23 Supplemental Coolant Additive Requirements{1352,1395,1063}

1992/11/23 New Gasket And Plate Used In Front Housing Group To Help Prevent Oil Leaks{1151}

1992/11/16 New Cylinder Head Gasket, Spacer Plate And Head Bolts Used; New Cylinder Liner Projection Measurement Method; New Cylinder Head Torque Sequence{1124,1221,1216}

1992/11/16 New Spacer Plate Gasket Provides Improved Sealing Around Push Rod Compartment{1221}

1992/11/30 New Fuel Priming Pump Kit Available{1258}

1992/11/30 Procedure To Replace Cylinder Head Gasket{1124}

1992/11/30 Procedure To Clean High Performance Marine Engine Air Filter{0374,1054}

1992/11/30 New Cast Iron Deaerators Replace Former Aluminum Deaerators{1350}

1992/12/21 New Cylinder Head Bolt Tightening Procedure{1100}

1992/12/21 Modifying Former 2W8888 Rocker Arm Shaft For Use With New 8T7581 Rocker Arm Shaft Bolt{1102}

1992/12/21 New Bellows Assemblies Used In Turbocharger Groups{1052,1059}

1993/01/18 New Videotape "Detection of Air and Combustion Gases in the Cooling System" Available {0374,1350}

1993/01/18 Part Number References For 0R2818, 0R2819, And 0R3231 Remanufactured 3208 Truck Engines {0374}

1993/01/18 Cylinder Pack Puller Groups Improved {0705,1239}

1993/01/18 New And Remanufactured Fuel Injector Reference {1290}

1993/01/18 New Grommets With Higher Temperature Capacity Used In Clamp Assemblies {1307,1052}