COUPLING GP-PUMP 1539577 - Caterpillar

Location of the 4P2383 Adapter (1) and 9Y3778 Impeller (2).Adaptable To: The new cast iron 9Y3778 Impeller replaced the former 9Y5651 Impeller in the 4P2152 Basic Water Pump Group and its equivalent Remanufactured 0R2856 Water Pump Group before these pumps were replaced by the new 1025941 Basic Water Pump Group and its equivalent Remanufactured 0R3790 Water Pump Group. The 1025941 and 0R3790 Basic Water Pump Groups also use the new cast iron 9Y3778 Impeller. See the Reference Article "New Water Pump Groups Use Tapered Roller Bearing" in this issue. The new cast iron 4P2383 Adapter replaced the former 9Y5652 Adapter in the higher level 9Y5647 Water Pump Group at the same time the impeller was changed in the 4P2152 Basic Water Pump Group.The new cast iron 4P2383 Adapter can be used with the former 9Y5651 Impeller. However, when using the former 9Y5652 Adapter with the new 9Y3778 Impeller in the 4P2152, 1025941, 0R2856 or 0R3790 Basic Water Pump Groups, the clearance between the adapter and the impeller MUST be checked. There is a possibility of interference due to the profile differences between the new 9Y3778 Impeller and the former 9Y5652 Adapter. See the Reference Special Instruction.
The former 9Y5652 Adapter is also not compatible with the non-metallic 7C5479 Impeller. See Reference Article Truck Engine News, February 1990, Page 1, "Improvements Made To Water Pumps; New Groups/Parts Available For Certain Applications ".
Damage to other engine components, such as cylinder liner pitting, can be caused by coolant with no or a low concentration of coolant conditioner. See the Reference Caterpillar publication "Coolant and Your Engine," Form No. SEBD0970. Also, see the Reference Articles Truck Engine News, September 1987, Page 2, "Recommendations For Preventing Cooling System Damage" and Truck Engine News, November 1992, Page 5, "Supplemental Coolant Additive Requirements".