2005/12/05 Caterpillar

Engine:

3512 (S/N: 1LM1-UP)

3512B (S/N: 2AF1-UP; 3KD1-UP)

3512 and 3512B Engines that are used for offshore oil well service are subject to extreme corrosion of external components. This can result in shorter intervals between engine overhauls.

A plan has been developed for improved corrosion protection for these engines. The plan includes revised components, new coatings, and new sealants. Some existing components are corrosion resistant and will remain as part of the standard offering.

These engines receive multiple coats of epoxy and urethane after final assembly. The following parts, practices and procedures will serve to enhance corrosion resistance:

• Caulk all joints and gaps that may retain water. Use 3M Ultrapro Autobody Sealant or an equivalent product. This is done prior to the surface preparation and final coating of the engine. This procedure will prevent corrosion on the metal that is below the external protective coating.

• Cover the exposed heads of bolts with silicone rubber caps capable of withstanding temperatures up to 316 °C (600 °F). These 28.6 mm (1.125 inch) caps are available from silicone cap suppliers. Retain the silicone caps with a non-acidic silicone adhesive such as Dow Corning 735 or Dow Corning 3145 RTV - Gray. These products are suitable for the temperatures that are encountered with cylinder head bolts. This will reduce corrosion of the bolt heads in order to simplify standard disassembly.

• Apply coatings that are resistant to corrosion such as High Performance Coatings H-11 to the following external aluminum engine components: valve covers, cam covers and other removable access covers.

The corrosion resistant parts are listed in Tables 1 and 2.

Note: The parts that are listed in bold are the groups for the subsequent parts.