Product Description
CUMMINS 3802565 OEM ENGINE PISTON KIT (.040) – RAM 5.9L 12-VALVE (1994–1998)
The genuine CUMMINS 3802565 OEM .040 oversize piston kit is engineered for builders restoring a 5.9L 12-valve Cummins to factory performance and reliability. Designed for engines requiring a .040” oversize bore, this OE piston assembly meets Cummins metallurgy, weight balance, and thermal expansion requirements, ensuring long service life under towing, work, and high-load conditions. This kit includes the piston, wrist pin, retainers, and piston ring set, making it a complete drop-in replacement for professional engine rebuilds.
Whether refreshing a high-mileage daily driver or completing a performance engine build, this factory-spec Cummins piston kit delivers unmatched durability, proper compression height, and perfect combustion chamber geometry. Pair it with genuine Cummins bearings, gasket sets, and valve train parts for a complete OE-level overhaul.
Key Features
- Genuine Cummins OEM piston kit — not aftermarket or reboxed.
- .040 oversize for engines requiring a precision rebore.
- Matched piston, ring set, wrist pin, and retainers included.
- OE alloy construction maintains factory heat expansion characteristics.
- Correct weight classing ensures balanced rotating assembly operation.
- Ideal for full engine overhauls in 12-valve 5.9L Cummins trucks.
Fitment Details
- Engine: 5.9L Cummins 6BT / 12-valve
- Model Years: 1994–1998 Ram 2500/3500
- Fuel Systems: VE and P7100 (P-pump) engines
- Oversize: .040" (requires block machining)
Important: Always measure cylinder bores and verify correct oversize before ordering. This piston will NOT fit standard or other oversize configurations.
Cross-Reference & Related Cummins Parts
Recommended genuine Cummins components to pair with this piston kit:
- CUMMINS 3802755 OEM PISTON RING SET – 5.9L CUMMINS
- CUMMINS 3802070 MAIN BEARING SET – STANDARD
- CUMMINS 3802150 ROD BEARING SET – STANDARD
- CUMMINS 3804896 12V UPPER GASKET SET
Common cross-reference identifiers: 3802565, 3802565-040, 3802565RX (reman program reference), 3802755 (ring set used with this piston type).
Installation Notes
- Confirm exact oversize with machine shop measurements before ordering.
- Always check piston-to-wall clearance per Cummins specifications.
- Ensure rings are installed with proper orientation and end gap spacing.
- Verify correct rod orientation and piston bowl alignment.
Specifications for cummins 3802565
| Attribute | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Cummins Part Number | 3802565 |
| Oversize | .040" (1.0mm) |
| GTIN | 088555943673 |
| UPC | 88555943673 |
| Engine Compatibility | 5.9L 12-valve Cummins (1994–1998 Ram 2500/3500) |
| Included in Kit | Piston, rings, wrist pin, retainers |
| Cross Reference | 3802565-040, 3802565RX, 3802755 ring set |
| Shipping Weight | Approx. 3.1 lbs per piston kit |
| E-Codes | Applicable to 6BT automotive diesel engine family; verify per vehicle documentation |
| Typical Shipping Method | UPS/FedEx Ground, ships from CPP Diesel warehouse |
| Prop 65 Warning | WARNING: This product may expose you to chemicals known to the State of California to cause cancer and reproductive harm. Visit www.P65Warnings.ca.gov for more information. |
Frequently Asked Questions
IS THIS A GENUINE CUMMINS PISTON KIT?
Yes — CPP Diesel supplies this as a 100% genuine Cummins OEM piston kit, complete with rings, wrist pin, and retainers.
WILL THIS FIT MY 5.9L 12-VALVE WITHOUT MACHINING?
No. This is a .040 oversize piston and requires the block to be bored and honed to the correct oversize.
DOES THIS KIT INCLUDE PISTON RINGS?
Yes. The kit includes the correct ring set, matched to this piston design.
HOW MANY KITS DO I NEED FOR A COMPLETE ENGINE?
You will need six (6) piston kits for a full 5.9L Cummins rebuild.
DOES THIS WORK WITH BOTH VE AND P-PUMP ENGINES?
Yes — it fits both VE and P7100 12-valve engines used from 1994–1998.
