Product Description
CUMMINS 3957544 OEM ENGINE OIL COOLER – 6BT/ISB 5.9L (1989–2002)
Keep your 5.9L Cummins alive under load with the genuine Cummins 3957544 OEM engine oil cooler. This stacked-plate cooler is the same design Cummins engineered to control oil temperature and protect critical components on 1989–2002 6BT/ISB engines in Dodge Ram 2500/3500 trucks. If your original cooler is clogged, leaking, or contaminated after a failure, this direct-fit replacement restores factory oil cooling performance and reliability.
Why Upgrade to a Genuine Cummins 3957544 Cooler?
- OEM-quality stacked-plate core engineered specifically for 5.9L 6BT/ISB engines.
- Helps maintain stable oil temperature and pressure under towing, tuning, and heavy work.
- Reduces risk of bearing, camshaft, and turbocharger damage from overheated or contaminated oil.
- Direct-fit replacement using factory gaskets and hardware – no modifications.
- Backed by Cummins engineering and CPP Diesel’s diesel-focused support.
Verified Fitment
Automotive (Dodge Ram):
- 1989–1993 Dodge D/W & Ram 2500/3500 – 5.9L 12V 6BT
- 1994–1998 Dodge Ram 2500/3500 – 5.9L 12V 6BT
- 1998.5–2002 Dodge Ram 2500/3500 – 5.9L 24V ISB (VP44)
Engine families commonly using 3957544 (verify by ESN):
- 4B3.9 / 6B5.9 B-Series industrial and on-highway applications
- ISB 5.9 automotive and medium-duty applications
- Selected off-highway and generator sets using B-series architecture (confirm by Cummins ESN)
Always confirm by engine serial number (ESN) or VIN for best results.
Best Practice: Replace Gaskets & Related Parts
Any time you service the oil cooler on a 5.9L Cummins, Cummins recommends replacing the cooler-to-block and cooler-to-filter head gaskets. CPP Diesel stocks the matching genuine Cummins parts so you can do the job once:
- Cooler-to-block gasket (1989–2002 5.9L): Cummins 4932124 OEM Oil Cooler Core Gasket
- Cooler-to-filter head gasket (1989–1996 12V): Cummins 3929792 OEM Oil Cooler Gasket
- Cooler-to-filter head gasket (1997–2002 12V/24V): Cummins 3942915 Oil Filter Head Gasket
Cross-Reference & Related Cummins Genuine Parts
The 3957544 cooler core is a later Cummins design that supersedes earlier oil cooler part numbers and pairs with other Cummins service parts:
- Supersedes / Cross-Refs (ID only): Cummins 3921558, Cummins 3942010, Mopar 4713985AB (ID reference only).
- Later 5.9L common-rail cooler (2003–2007): Cummins 3959031 OEM Engine Oil Cooler – ISB 5.9L (2003–2007)
- 6.7L cooler (2007.5–2024): Cummins 3975818 OEM Engine Oil Cooler – ISB 6.7L (2007.5–2024)
- Matching valve tappets for 12V/4BT/6BT: Cummins 3931623 OEM Valve Tappet (Lifter)
- Matching oil pump for 5.9L 12V/24V: Cummins 4939587 OEM Engine Oil Pump – 5.9L 12V/24V (1989–2002)
What’s Included
- (1) Genuine Cummins engine oil cooler core – Part #3957544
- Gaskets, hardware, and oil not included (sold separately)
Installation Tips
- Thoroughly flush the lubrication system after any bearing or turbo failure before installing the new cooler.
- Always install with new Cummins gaskets (see part numbers above).
- Torque all fasteners to Cummins spec and re-check for leaks after the first heat cycle.
- Change engine oil and filter after installation; repeat if contamination was present.
Specifications for cummins 3957544
| Spec | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Part Number | 3957544 |
| UPC | Not specified by manufacturer (distributors may use their own UPC for this part) |
| GTIN | Not specified by manufacturer (search “Cummins 3957544 GTIN” for distributor-specific codes) |
| Engine Compatibility | 5.9L 6BT & ISB B-Series; commonly used on 1989–2002 Dodge Ram 2500/3500 5.9L 12V & 24V; also used on select B-series industrial/off-highway engines (verify by ESN). |
| Vehicle Fitment (Primary) | 1989–2002 Dodge Ram 2500/3500 with 5.9L 12V or 24V Cummins (non-common-rail) |
| Cooler Type | Stacked-plate engine oil cooler core |
| Quantity Required | 1 per engine |
| Cross Reference (ID only) | Cummins 3921558, Cummins 3942010, Mopar 4713985AB (ID reference only, use 3957544 for OE replacement) |
| Companion Gaskets | Cooler-to-block: 4932124; cooler-to-filter head: 3929792 (’89–’96), 3942915 (’97–’02). |
| Shipping Weight | Approx. 3 lb (core only) |
| Shipping Dimensions (Box) | Approx. 33 in (L) x 19 in (W) x 17 in (H) |
| Shipping Info | Typically ships free via standard ground service within the continental U.S. from CPP Diesel. |
| E-Codes | Not applicable (engine lubrication component; no lighting/emissions E-code) |
| Country of Origin | Not specified (genuine Cummins component; origin may vary by production batch) |
| Prop 65 Warning | This product can expose you to chemicals known to the State of California to cause cancer and reproductive harm. For more information, visit www.P65Warnings.ca.gov. |
FAQ
WILL THIS FIT MY 1989–2002 5.9L CUMMINS DODGE RAM?Yes. Cummins 3957544 is the OEM engine oil cooler core for most 1989–2002 5.9L 12V and 24V (VP44) Ram 2500/3500 applications. For industrial or non-Dodge uses, always confirm by engine serial number (ESN) before ordering.
DOES THIS COOLER COME WITH GASKETS OR HARDWARE?
No. This listing is for the cooler core only. CPP Diesel recommends pairing it with genuine Cummins gaskets for a leak-free install: 4932124 (cooler-to-block), 3929792 (’89–’96 cooler-to-filter head), and 3942915 (’97–’02 cooler-to-filter head).
WHAT’S THE DIFFERENCE BETWEEN 3957544 AND 3959031 OR 3975818?
Part 3957544 is the correct OEM cooler for non-common-rail 5.9L (1989–2002). The Cummins 3959031 cooler is used on 2003–2007 common-rail 5.9L trucks, and Cummins 3975818 is used on 6.7L applications. Use the part that matches your model year and engine.
HOW DO I KNOW MY OIL COOLER NEEDS TO BE REPLACED?
Common signs include low or unstable oil pressure, oil/coolant cross-contamination, or metal debris found in the oil after a bearing or turbo failure. Because stacked-plate coolers are almost impossible to fully clean, replacement is the safest option whenever contamination is suspected.
IS THIS A GENUINE CUMMINS PART OR AFTERMARKET?
This is a genuine Cummins OEM cooler (part #3957544), sourced through CPP Diesel’s Cummins parts channel. It is not an aftermarket reproduction, ensuring OE fit, flow, and durability.
