1988/10/03 Caterpillar

Check Valve Added To Keep Air From Entering Fuel System {1264}

Usage:

3208 Engines In All Applications

Description of Change: On 3208 Engines, it is possible for the fuel transfer pump to have enough suction pressure to suck air past the seal around the governor main shaft. To prevent this, a check valve has been added to the governor housing at the housing cavity for the shaft seal and bearing. See illustration.

Location of check valve added to the governor housing.

The check valve limits the pump suction pressure inside the cavity and prevents entry of air by the shaft seal. This minimizes the possibility of low power and hard starting.

Adaptable To: The 9Y4966 Valve Assembly is effective with the following 3208 Engines:

Truck Engines-51Z78436, 2Z50795

Vehicle Engines-79V18652

Industrial Engines-90N70907, 3Z7742

Marine Engines-75V9816, 1Z15404

Generator Sets-29A2103, 30A3418

The valve can be installed in the governor housing on earlier engines by reaming out the existing hole near the main shaft seal as shown. The valve is preset to open at the proper suction pressure and this setting should not be changed.

Caterpillar Information System:

1988/09/26 Multipurpose Storage And Handling Systems For Parts {1100,0660}

1988/09/26 New VR3 Regulator Has Improved Short Circuit Protection {4474}

1988/09/19 Caterpillar Introduces A "Hotline" For Medical Information On Hazardous Materials (U.S. And Canada){0353,0373}

1988/09/19 New Service Tools Available{0600}

1988/09/19 Bellows-Type Exhaust Seals Used On Water Cooled Turbochargers{1059,1070}

1988/09/19 New Heat Sinks Have Solid Diode Wires{4472}

1988/09/19 New Dipstick, Breather, And Oil Filler Cap Minimize Oil Leakage{3311,3354}

1988/09/05 Improved Air Cleaner Element Has Pleats That Are Evenly Spaced{1054}

1988/09/05 New Piston Cooling Jets Used{1331,1200}

1988/09/05 New Rocker Arm Shaft Assembly and Bolts Used{1102}

1988/08/29 New Exhaust Manifold System Used {1059}

1988/08/29 New Piston Body Assembly Reduces White Smoke During Cold Weather Starts {1214}

1988/10/03 Main Rotor Shaft Changed to Eliminate Loose Connecting Bolts {4457}

1988/10/03 Tool Storage For Centurion Track Press Tools {4150,0660,0729}

1988/10/17 New Service Tools Available{0600}

1988/10/17 Self-Locking Bolts Used In Front Timing Gear Group{1206}

1988/10/17 New Woodward Actuator Assembly (EG10P) Has Lower Relief Valve Setting{1289}

1988/10/24 New Graphite Exhaust Manifold Gasket Replaces Stainless Steel Gasket{1059}

1988/10/24 New Flywheel Assemblies Used In With Rear PTO Arrangements{1156}

1988/10/24 Head Bolt Holes In Cylinder Blocks Can Be Repaired{1201,1101}

1988/10/24 Seal Retainer And Seals Are Required When A New Cylinder Head Assembly Is Installed{1100}

1988/10/31 New Fuel Shutoff Solenoid Assembly Used{1259}

1988/10/31 New Air Cleaner Group Has Improved Crankcase Fumes Disposal{1051,1054,1317}

1988/11/07 New Oil Pressure Sender Assembly Used{7455}