1986/12/15 Caterpillar

Silicone Water Seal Available{1101}

Usage:

D346, D348, D349 Engines

SUPPLEMENT: 07/04/88

SERVICE MAGAZINE; DECEMBER 15, 1986; PAGE 10; "Silicone Water Seal Available" for D346, D348, D349 Engines. The part number "8S4247" in the third line of the article is incorrect. The correct part number is 8S4275.

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SUPPLEMENT: 03/28/88

SERVICE MAGAZINE; DECEMBER 15, 1986; PAGE 10; "Silicone Water Seal Available" for D346, D348, D349 Engines. Additional information for this article follows.

If 6V2555 or 6V2556 Gasket Kits are ordered, be sure 8S4275 Water Seals (Silicone) are included. The 8S4275 Water Seal (Silicone) is gray with a brass insert. The 2W3797 Water Seal (EPDM Rubber) is black with a blue plastic insert. The 2W3797 Water Seal should not be used.

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The 8S4275 Water Seal should be used on the D346, D348 and D349 Engines. At one time it was recommended that the 8S4295 Water Seal (Silicone) be replaced with the 2W3797 Water Seal (EPDM Rubber). That is no longer true. The EPDM seal cannot be used where the seals come in contact with oil. The design of the above engines allows oil between the cylinder head and block to come in contact with the water seals. This could cause the EPDM water seals to swell and deteriorate which could cause a coolant leak. Therefore the 2W3797 Water Seal (EPDM Rubber) should not be used. The 8S4275 Water Seal (Silicone) is highly resistant to oil.

Caterpillar Information System:

1986/12/15 Avoid Oil Contact With New Water Passage Seals Used In Cylinder Head Groups{1100}

1986/12/15 Check For Dirt Before Replacing Pyrometer Switch{1050,7466}

1986/12/15 New Track Press Assembly Specifications Decals Available{4150}

1986/12/15 How To Use Literature References In Column Three of the NPR (Numerical Parts Record){0374}

1986/12/01 Improved Retaining Bushing In Fuel Injection Pump {1251,1250}

1986/12/01 Use Correct Pistons And Rings For 3406B Truck Engines {1214,1215}

1986/12/01 Hour Meters - Mechanical Versus Electronic {7480,7478}

1986/12/01 Product Support Literature For Military Machines {7567}

1986/11/24 Engine Mounts Available To Provide Clearance For Deep Oil Pans{1152,1302}

1986/11/24 Updates To The Parts Book Microfiche{0374}

1986/11/24 Smaller Diameter Fuel Supply Line May Cause Power Loss{1274,1250}

1986/11/10 Use Gas Detector Tubes That Have Expired Dates To "Break In" The Combustion Chambers For The Fuel Sulphur Analyzer Group{0651}

1986/12/15 New Cover Used On BrakeSaver Control Valve{1159}

1986/12/22 Two New Shop Towels And Towel Bracket Available In North America{0600}

1986/12/22 Engine Power Increased{1250}

1986/12/22 Use Heli-Coils To Repair 5.4" Bore Engine Rocker Arm Assemblies{1123,1105}

1986/12/22 Fuel Dilution Troubleshooting Procedure{1250}

1986/12/22 New Oil Level Gauges (Dipsticks) With "Full Range" Used{1326}

1986/12/22 New Torque Control Group Used In Governor And Fuel Injection Pump Group{1264}

1977/01/17 Removal Of Bolts With Metal Locks Easier With New Sockets{0610}

1977/01/17 Improved Main And Connecting Rod Bearings Have Aluminum Alloy With More Strength{1230}

1977/01/17 Blades For Hose Saw Cut Off Group Must Now Be Sent To New Address To Be "Resharpened"{0664}

1977/01/17 New Special Instruction For Troubleshooting 5P2150 Engine Horsepower Meter{0651,1250}

1977/01/17 SIRS Component Code List{0331}