NUT-FACE SEAL 6V8558 - Caterpillar

Caterpillar: Confidential Yellow
PSP FOR TURBOCHARGER SURGE AND HIGH EXHAUST TEMPERATURE PROBLEMS ON CERTAIN 3508 GENERATOR SET ENGINES - MAILED US AND CAN ADA, CACO, COFA, LIMITED COSA - REVISED 1/89
  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.
(Revised January 1989) U-39 A-22 AU-24 E-21 O-25.2 1059 PS4197 This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4197" as Part Number and "7755" as Group Number. This Revised Service Letter replaces the March 9, 1988 Service Letter. Changes have been made to the Affected Product and to the Termination Date. Termination Date
January 31, 1990
Problem
Only the higher rated 50Hz/60Hz prime power and standby 3508 Generator Set Engines are affected. The specific serial numbers are shown below. The Affected Products experience turbocharger surge problems while operating near full load or when accepting large block loading. The turbocharger surge is caused by uneven firing pulses in the two exhaust manifolds. Some of the engines listed below have one or two tubes connecting the inlet manifold to the exhaust elbow to minimize turbocharger surge. However, the addition of the tube(s) may result in high exhaust temperatures at rated or near rated loads. The elimination of these tubes and the addition of the new exhaust manifold parts will even out the firing pulses, eliminate the turbocharger surge and reduce exhaust