Product Description
CUMMINS 4089181 OEM PISTON RING SET (.020 OVER) – RAM 5.9L ISB (2003–2007)
The genuine CUMMINS 4089181 .020 over piston ring set is engineered specifically for the 2003–2007 5.9L ISB Cummins engine found in Ram 2500 and 3500 trucks. When building or overhauling a 5.9L common rail engine, using an OEM ring pack ensures factory-level sealing, oil control, heat resistance, and longevity. These rings restore compression, reduce blow-by, and maintain proper cylinder lubrication—critical for both stock and performance applications.
Oversized rings such as .020 over (0.50mm) are used when the cylinders have been bored or honed beyond standard diameter. Cummins ring metallurgy and profile geometry outperform aftermarket alternatives, especially in high-load diesel environments.
Key Features
- Genuine Cummins OEM ring pack – ensures correct tension, wear resistance, and seal profile.
- Perfect for .020 over (0.50mm) cylinder bores after machining.
- Designed for 5.9L ISB common rail engines (2003–2007 Ram applications).
- Improves compression, reduces blow-by, and restores engine efficiency.
- High durability materials for extreme cylinder temps and diesel combustion pressure.
Fitment Details
- Engine: Cummins 5.9L ISB Common Rail
- Years: 2003–2007
- Vehicles: Dodge Ram 2500 & 3500
- Oversize: .020 Over (0.50mm)
- Note: Always measure bore and verify oversize before ordering.
Cross-Reference & Companion Cummins Parts
CPP Diesel carries supporting Cummins OEM components commonly replaced during a full 5.9L ISB rebuild:
- CUMMINS 3950661 OEM PISTON (STANDARD)
- CUMMINS 4089649 MAIN BEARING SET
- CUMMINS 4025129 ROD BEARING SET
- CUMMINS 4891178 HEAD GASKET (5.9L)
- VIEW MORE GENUINE CUMMINS PARTS
Common Cummins cross-reference numbers: 4089181, 4089180 (family variations).
Installation Notes
- Measure bore diameter and confirm oversize before installation.
- File-fit if necessary depending on machining tolerances.
- Install piston rings with correct orientation and stagger gaps properly.
- Always check ring end-gap per Cummins specifications.
Specifications for cummins 4089181
| Attribute | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Cummins Part Number | 4089181 |
| Oversize | .020 Over (0.50mm) |
| Engine Compatibility | 5.9L ISB Common Rail (2003–2007) |
| Vehicle Fitment | Dodge Ram 2500 / 3500 |
| UPC | 190910392672 |
| GTIN | 190910392672 |
| Shipping Weight | Approx. 1.2 lbs |
| Shipping Method | Standard ground; expedited available |
| E-Codes / Emissions | Non-emissions component |
| Prop 65 Warning | WARNING: May expose you to chemicals known to cause cancer and reproductive harm. See www.P65Warnings.ca.gov. |
| Country of Origin | As labeled by Cummins (varies by batch) |
Frequently Asked Questions
HOW DO I KNOW IF I NEED .020 OVER PISTON RINGS?
.020 over rings are required when your engine cylinders have been bored or honed to an oversized specification. Always measure cylinder bore and verify machining dimensions.
WILL THIS FIT MY 2003–2007 5.9L CUMMINS?
Yes—CUMMINS 4089181 fits all 2003–2007 5.9L ISB engines, provided the cylinders have been machined to .020 over.
ARE THESE GENUINE CUMMINS RINGS?
Yes, CPP Diesel supplies only genuine Cummins OEM piston rings for maximum durability and sealing.
SHOULD I REPLACE THE PISTONS TOO?
Many rebuilders install new pistons when going oversized. CPP Diesel carries genuine Cummins pistons such as CUMMINS 3950661.
DO I NEED TO FILE-FIT THESE RINGS?
Depending on machine shop tolerances, file-fitting may be needed. Always check end gaps per Cummins specifications.
