One New Aftermarket Replacement Water Pump Group Fits Various Fits Caterpillar Industrial Construction Engine Model: 31161. They Are Put Through A Wash Process To Clean The Casting and Machining Debris To Ensure Any Foreign Particles Are Removed.2. Better Casting Finish Of Our Pumps Increases Pump Performance and Durability3. All Impellers Are Balanced To Improve Pump Performance and Reduce Vibration.4. All Internal Components Are Made To Specifications To Ensure Components Fits Properly5. Come Conveniently Packed In Foam To Ensure The Preservation Of The Product Through Transportation and Storage. All Pumps and Components Are Properly Packed and Protected To Avoid Rusting6. Come With A Stainless Steel Shaft To Increase The Longevity Of The Pump, While Competitors Use A Carbon Steel Shaft.Replaces Part Numbers: 4P3683, Csu80-0066