VALVE GP-CONTROL 4T2747 - Caterpillar

Caterpillar: Confidential Yellow
PRIORITY:RETIGHTEN CRANKSHAFT COUNTERWEIGHT BOLTS; REPLACE BOLTS IF NECESSARY 3508, 3512 ENGINES - PI3005 - MAILED US AND CAN ADA, CACO, COFA, CFEL, BRAZIL, COSA
  The information supplied in this service letter may not be valid after the termination date of this program.   Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
RETIGHTEN CRANKSHAFT COUNTERWEIGHT BOLTS; REPLACE BOLTS IF NECESSARY 3508, 3512 Engines, 1202, PI3005 U-25 A-23 AU-20 B-11 C-24 E-22 O-19 PRIORITY Problem The listed 3508 and 3512 Engines may have loose or improperly tightened bolts in the crankshaft counterweights. One or more loose bolts causes the bolts to bend and the connecting rod can interfere with the counterweight. This breaks the counterweight bolts and the weight is thrown through the block, usually destroying the engine. A special lubricant instead of engine oil is now used on the bolts to prevent any damage to the mating parts when the bolts are tightened, and a tighter torque-turn method is used. Affected Engines And Parts If Needed All the listed engines are included in this Priority Program. 3508 Industrial Engines 95Y1-95Y611, 613-616 3508 Industrial Engines - Slow Speed 68Z1-68Z675 3508 Marine Engines 96Y1-96Y584, 586-599 3508 Marine Engines - Slow Speed 69Z1-69Z252 3508 Generator Sets 23Z1-23Z448 3508 Generator Sets - Slow Speed 70Z1-70Z549 3512 Industrial Engines 49Y1-49Y354, 359, 360, 367, 379-382, 389, 390, 397, 404-408, 410 3512 Industrial Engines - Slow Speed 65Z1-65Z589 3512 Marine Engines 50Y1-50Y496 3512 Generator Sets 24Z1-24Z423, 425-431, 433-437, 439-443, 445-447, 449-479, 481-492, 494-500, 502-575, 577-640 3512 Generator Sets - Slow speed 67Z1-67Z485, 487-491 3512 Vehicular Engines 51Y1-51Y450, 452-454, 456, 458-461, 465-467 Parts needed, if any, are 1N3212 Bolts. Many engines will require none and some may require a quantity of new bolts. Action Requested The following procedure applies to all the engines listed. Do this work immediately, giving priority to users' engines. Take a quantity of new 1N3212 Bolts to the job site so new bolts can be installed if needed. Do the following procedure, one bolt at a time: 1. Loosen the crankshaft counterweight bolt about one full turn, noting whether or not the bolt seems to turn without any unusual amount of effort. If the bolt backs out one full turn and appears to be free of any unusual amount of effort or resistance, simply tighten the same bolt back to a torque of 50 +/- 5 N X m (37 +/- 4 lb ft). Now, tighten the bolt an additional 1/3 turn (120 +/- 5 deg.). OR 1a. If a bolt seems to require too much effort when it is loosened one full turn, remove the bolt. The bolt threads could be damaged. Do not use this bolt. 1b. Inspect the threads in the crankshaft and look for debris in the threads. 1c. Remove any debris and use a tap (5/8"