1993/07/12 Caterpillar

Magnetic Switches (Relays) May Be Intermittent{1400}

Usage:

The 3T0376 (24V) and the 9X0253 (12V) Magnetic Switches used as power relays on machines may be intermittent. White corrosion on the nuts of the power studs for the relay contacts may cause an open circuit condition. Instead of replacing the relay, the corrosion can be cleaned from the nuts by lightly wire brushing the nuts to remove the corrosion. Apply a thin coat of Dielectric 8T9020 Grease to the connection at assembly. Effective with date code 40M (40=40th week M=1992) the plating has been improved to help prevent the white corrosion of the nuts.

NOTE: Be sure to open or turn off the battery disconnect switch before servicing the 3T0376 or 9X0253 Magnetic Switches. On 12 Volts Machines without a battery disconnect cable switch, open the battery disconnect cable between the negative terminal of the battery and frame ground of the machine.

Caterpillar Information System:

1993/07/05 New Cast Iron Inlet Adapter And Impeller For Water Pumps {1361}

1993/07/05 New Water Pump Groups Use Tapered Roller Bearing {1361}

1993/07/05 New Stronger Elbow Used In Marine And Fire Pump Engine Water Lines Groups {1380}

1993/07/05 False Logging Of 100-01 Low Oil Pressure, And 100-11 Very Low Oil Pressure Diagnostic Codes {1902}

1993/06/21 New Cylinder Head Assembly Provides Improved Valve Seat Retention{1100,1103}

1993/06/21 New G3500 Gas Engine Performance Manual Available{0376}

1993/06/21 Measuring "Dynamic Rack" Of Unit Injectors{0780}

1993/06/21 Windshield Washer Jet Nozzle Assembly Available For Parts Service{7306}

1993/06/14 3E3761 Coolant Level Sensor Assembly {7422}

1993/06/14 New Bonnet Used In Fuel Injection Pump Group {1251}

1993/06/14 New Fuel Pump Drive Idler Gear Assembly And Shaft Used In Front Timing Gear Groups {1206}

1993/06/14 Lock Removed From Front Timing Gear Group To Help Prevent Loss Of Tightening Torque {1206}

1993/07/12 Improved Voltmeters Available{7450}

1993/07/12 Preventive Maintenance To Reduce Risk Of Stator Failure{1404,4453}

1993/07/12 The Latest "Gas Engine Installation Drawings" Are Available{0374}

1993/07/19 Manifold Pressure Variation at Full Load/Constant Speed{1058}

1993/07/19 Regulator Assemblies Available To Service Thermostatic Valve Groups{1355}

1993/07/19 Prechamber Rust Removal{1106}

1993/07/26 Compressor Nut Torque For Schwitzer Turbochargers{1052}

1993/07/26 Engine Changes For 350 Hp{1022}

1993/07/26 Diesel Truck Engine Smoke Limits{1250}

1993/07/26 G3400 Engine Performance Manual{0376}

1993/07/26 New Exhaust Manifold End And Center Sections Used In Dry Type Exhaust Manifold Groups{1059}

1993/07/26 Improved Mounting Reduces Vibration To Liquid Level Switch{7470}