RING-SNAP 1L8497 - Caterpillar

Engines: Commercial
All 3500 DieselDescription of Change: The oil seals have been removed from the exhaust valves in the basic cylinder head groups that are used on 3500 Commercial Engines. This oil seal has been removed in order to help prevent the buildup of deposits on the exhaust valve stem. These deposits may occur on engines that operate for extended periods of time with the following conditions:
Temperatures that are below 0 °C (32 °F)
Low loads
Low RPMAdaptable To: The 137-6856 Seals (Oil) have been removed from the exhaust valves in the basic cylinder head groups that are used on 3500 Commercial Engines. This change is effective with the commercial engines that are listed in Table 1.Cylinder heads that do not include oil seals on the exhaust valves should be used for top end overhauls and major overhauls. The cylinder heads without oil seals on the exhaust valves can be used individually for repair of cylinder head damage. When a cylinder head is rebuilt, that cylinder head should not include oil seals on the exhaust valves. Remanufactured cylinder heads that have date codes from UUNN (November 2000) and later than November 2000 do not include oil seals on the exhaust valves. Table 2 provides part numbers for the basic cylinder head groups.
Table 1
Engine Serial Number For Removal Of The 137-6856 Seal (Oil)    
Model    MUI Engine
Serial No.    EUI Engine
Serial No.    B Series Engine
Serial No.    
3508 Industrial     95Y1127, 68Z1154         S/N:CBB120
   
3508 Marine     96Y1981, 69Z875     3PS197     S/N:7SM419, 8KN416, 2BM153, 3DM207, 1TW272, 3DW162
   
3508 Generator Set     23Z7770, 70Z1061     S/N:5XM32, 3LS228
    S/N:6PN716, 4GM656, 2HW162
   
3508 Vehicular     97Y733            
3508 Locomotive             5PS265    
3508 Military     S/N:3HM15, 9WN16
        S/N:BAG10
   
3508 Captive Generator Set     S/N:1JZ221
        S/N:1FZ600
   
3512 Industrial     S/N:49Y967, 1LM214
        S/N:2AF200, 8DF187, BRC147
   
3512 Marine     50Y1742, 66Z900     3RS340     S/N:4TN379, 8EM353, 2EZ232, 1PW362, 2GW278
   
3512 Generator Set     24Z9874, 67Z1914     3MS233     S/N:8RM602, 6WN711, 5AW117, 4AW430
   
3512 Vehicular     51Y843            
3512 Locomotive         2WK84     3ZW206    
3512 Military             4DR2    
3512 Captive Generator Set     S/N:1KZ308
    S/N:
    S/N:1GZ376
   
3516 Industrial     S/N:27Z813, 71Z362
    S/N:
    S/N:9WF118
   
3516 Marine     S/N:29Z1362, 72Z559
    S/N:3SS324, 3XS408
    S/N:8KN416, 8CN181, 9AN201, 4BW362, 2FW207, 3CW243
   
3516 Generator Set     S/N:25Z6946, 73Z947, 5SJ7733
    S/N:7KM75, 3NS246
    S/N:7RN1641, 6HN1341, 2JW294, 1NW134
   
3516 Vehicular     S/N:28Z653
    S/N:
    S/N:
   
3516 Locomotive     S/N:9KF114
    S/N:
    S/N:BCK231
   
3516 Military     S/N:
    S/N:3JS9, 2TS8
    S/N:
   
3516 Captive Genertor Set     S/N:1LZ227
    S/N:
    S/N:1HZ290
   
Table 2
Reference For Basic Cylinder Head Groups    
Model    Part Number For Basic Cylinder Head Group    Part Number For Remanufactured Cylinder Head    Part Number For Upgrade To New Cylinder Head    
3500B     145-3216     0R-9472     0R-9473    
3500 MUI     172-0835     0R-9775     0R-9773    
3500 EUI     172-0837     0R-9777     0R-9778