78065A 1 Mercury PLATE ASSEMBLY, EXHAUST

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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 equipped with a 3116 Truck Engine having engine serial numbers beginning with 2BK are not affected (1991 Emissions).
Parts Needed
1 - 7E5254 Regulator - Temperature (7SF1-12502 Only) 1 - 7E9425 Coolant Temperature Switch 1 - 3J1907 O-Ring Seal (Coolant Temperature Switch) 1 - 3K0360 O-Ring Seal (Heater Return Line to Water Pump Housing) 1 - 4P2684 Gasket - Water Regulator (7SF1-12502 Only) 1 - 4P6602 Module Heater Control 2 - 2S3440 Clamp (Radiator End Tank Nipple cap and Heater Hose to Water Pump) 1 - 6V1438 Connector (Heater Return Line to Water Pump Housing) 1 - 4W5140 Plate (Use to correct the Engine Information Plate) 6 - 9Y7355 Seat (Valve Spring) 1 - * Cap-Radiator End Tank Nipple 1 - ** Winter front * General Motors Part Number 15544596 or similar can be used. ** Procured from local supplier (Note: In Canada, GM part number 10952232 Winter Front is available.)
Action Required
(Refer to the attached procedure for specific instructions) 1. If applicable, make sure the October 20, 1990 Service Letter - PS4530 has been completed. (Product Support Program For Installing Stronger Exhaust Valve Push Rods On Certain 3116 Truck Engines) 2. Install a winter front that can be opened as described below. (Installation subject to customer approval.) ... The front should have a minimum opening dimension of at least 387 sq. cm (60 sq. in.) ... The front should be fastened to the hood and cover the entire grill, including the gap around the grill between the edges of the grill and the hood. 3. Replace the 7E5561 Air Inlet Heater Control Module with a 4P6602 Control Module. See Part "A" of the attached rework procedure. The 7E5561 Module used a 7 minute "On" cycle. The 4P6602 module is "On" for 10 minutes, then cycles "On" 10 seconds, "Off" 10 seconds for an additional 10 minutes. 4. Replace the 7E6106 Coolant Temperature Switch in the regulator housing with a 7E9425 Switch and 3K0360 Seal. See Part "B" of the attached rework procedure. The former switch turned the air inlet heater off when the jacket water temperature reached 85 deg. F. The new switch turns the air inlet heater off when the jacket water reaches 120 deg. F. 5. On engines with serial numbers 7SF1-12502, replace the