SEAL-O-RING 9L5650 - Caterpillar

Caterpillar: Confidential Yellow
PSP FOR EXHAUST VALVE STICKING ON 1990 MODEL YEAR 3116 TRUCK ENGINES - PS4568 - MAILED US AND CANADA, LIMITED TRUCK TEPS - THI S SL EFFECTIVE NOVEMBER 1, 1990
  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.
(Effective November 1, 1990) U-49 TT-2.1 1272 PS4568 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 "PS4568" as Part Number, "7755" as Group Number, and "96" as Description Code. Whenever possible, this program should be implemented at the same time as the October 20, 1990 Service Letter - PS4530 and the January 20, 1991 Service Letter - PI1155. Although this program can be administered either before or after failure, (exhaust valve sticking) it is recommended that it be implemented before failure only in northern or high altitude climates that regularly have winter temperatures of -10 deg. C (15 deg. F) or lower. Do all applicable portions of this Service Letter. Termination Date
March 31, 1992
Problem
Exhaust valve sticking and/or excessive white smoke at startup has occurred on certain 3116 Truck Engines operating in areas with cold ambient temperatures. The items listed under Action Required help enhance the combustion process, reduce occurrence of white smoke, and reduce exhaust valve sticking. Field tests show good results in reducing both white smoke and exhaust valve sticking when all of these items have been completed.
Affected Product
Model Identification Number 3116 7SF1-Up (1990 Emissions) This program affects all 1990 and 1991 model vehicles with 3116 Truck Engines that have engine serial numbers beginning with 7SF. The 1991 or 1991-I vehicles