Product Description
CUMMINS 3975818 OEM ENGINE OIL COOLER – ISB 6.7L (2007.5–2024)
The CUMMINS 3975818 OEM ENGINE OIL COOLER is the genuine stacked-plate cooler core used on most 2007.5–2024 Ram 2500/3500 6.7L ISB Cummins applications. This OE cooler is engineered to stabilize oil temperature, maintain viscosity under load, and protect critical components like bearings, camshaft, and turbocharger in towing, work, and performance trucks.
Unlike universal or off-brand coolers, this is a direct-fit Cummins part with the correct sealing surfaces and flow paths for ISB6.7/QSB6.7 engines. If your truck is seeing low oil pressure, overheating, or signs of oil/coolant cross-contamination, replacing a clogged or failing cooler with genuine Cummins 3975818 is the right way to restore factory reliability.
Key Features & Benefits
- Genuine Cummins stacked-plate core for OE heat rejection and stable oil pressure.
- Direct-fit replacement for ISB 6.7L platforms with factory oil cooler housings.
- Helps prevent bearing, cam, and turbocharger failure caused by overheated or contaminated oil.
- Built to Cummins durability standards for long service life in heavy-duty use.
- Compatible with EPA13+ ISB6.7/QSB6.7 engine families when verified by ESN.
Verified Fitment – Automotive
Ram Truck Applications (Typical):
- 2007.5–2018 Ram 2500/3500, 6.7L ISB Cummins
- 2019–2024 Ram 2500/3500, 6.7L ISB Cummins (verify by VIN/ESN for late-model updates)
This cooler is commonly used on EPA13 ISB6.7 and QSB6.7 engine families in on-highway and select industrial/off-highway applications. Always confirm by engine serial number (ESN) before ordering for non-Ram uses.
Fitment notes:
- Designed as the OE cooler for most 2007.5–2024 6.7L Cummins Ram 2500/3500 trucks.
- Earlier 5.9L applications use different Cummins coolers (see Cummins cross-references below).
- Always replace required gaskets and verify torque specs per factory service information.
Cross-Reference & Related Genuine Cummins Parts (CPP Diesel)
Pair this cooler with the correct Cummins oil cooler gaskets, filter housing, and earlier-generation coolers when servicing multiple trucks or mixed-year fleets:
- CUMMINS 3977913 OEM ENGINE OIL COOLER GASKET SET – RAM 5.9L/6.7L (2003–2023) – OE gasket/seal kit for cooler service on ISB 5.9L & 6.7L.
- CUMMINS 3909355 OEM ENGINE OIL FILTER HEAD ADAPTER – RAM 5.9L/6.7L (2003–2011) – Adapter between the oil cooler and filter head on many ISB engines.
- CUMMINS 5289557 OEM ENGINE OIL FILTER HOUSING (OIL FILTER HEAD) – RAM 5.9L/6.7L (2003–2018) – Complete OE oil filter head housing for ISB engines.
- CUMMINS 3959031 OEM ENGINE OIL COOLER – ISB 5.9L (2003–2007) – Genuine 5.9L common-rail cooler for 2003–2007 Ram applications.
- CUMMINS 3957544 OEM ENGINE OIL COOLER – 6BT/ISB 5.9L (1989–2002) – Genuine 5.9L 12V/24V cooler for 1989–2002 Ram applications.
What You Get
- (1) Genuine Cummins stacked-plate engine oil cooler core – Part # 3975818
- Gaskets, hardware, and fluids sold separately.
Installation & Service Tips
- Inspect and flush the entire oil circuit after any internal engine or turbo failure.
- Always use new Cummins gaskets/seals when installing the cooler.
- Torque all fasteners to factory specifications and recheck after initial heat cycles.
- Change engine oil and filter immediately after cooler installation and again if contamination was present.
Specifications for cummins 3975818
| Brand | Cummins |
| Part Number | 3975818 |
| Product Type | Engine oil cooler core (stacked-plate) |
| UPC | 193807226602 |
| GTIN | 193807226602 |
| Shipping Weight | Approx. 6.6 lb (cooler only; packaged weight may vary) |
| Package Dimensions (L x W x H) | 32.00 in x 19.50 in x 7.50 in (approximate CPP Diesel shipping carton) |
| Engine / Application | ISB 6.7L Cummins (Ram 2500/3500 2007.5–2024, typical) and select ISB6.7/QSB6.7 EPA13+ applications – verify by VIN/ESN. |
| Cross Reference (ID Only) | Cummins: 3975818, 3051997, 3059666, 3066842, 3902372, 3902434, 3903375 Mopar: 68015126AA XDP: XD417 | Bostech: EOC03593 | Dorman: 918-335 | PAI: 141428 (CUP141428) |
| E-Codes | Not applicable (engine oil cooler – no lighting E-code certification required). |
| Prop 65 | WARNING: Cancer and Reproductive Harm – See www.P65Warnings.ca.gov. |
| Quantity Required | 1 per engine |
| Shipping Info | Free ground shipping in the continental U.S. from CPP Diesel on qualifying orders. |
FAQ
Will this oil cooler fit my 6.7L Cummins Ram?
In most cases, yes. Cummins 3975818 is the OE cooler core for 2007.5–2024 Ram 2500/3500 trucks equipped with the 6.7L ISB Cummins. Always confirm by VIN or engine serial number (ESN) if you are unsure, especially on late-model trucks and cab-and-chassis applications.
Does this Cummins 3975818 cooler include gaskets and hardware?
No. This listing is for the cooler core only. For a complete OE-quality repair, pair it with a genuine Cummins gasket/seal kit such as CUMMINS 3977913 OEM ENGINE OIL COOLER GASKET SET , plus any additional hardware specified by your service manual.
What should I use for older 5.9L Cummins trucks?
5.9L applications use different coolers. For 2003–2007 5.9L common-rail trucks, use CUMMINS 3959031 OEM ENGINE OIL COOLER . For 1989–2002 5.9L 12V/24V trucks, use CUMMINS 3957544 OEM ENGINE OIL COOLER .
How do I know my existing oil cooler needs to be replaced?
Common symptoms include low or fluctuating oil pressure, engine overheating under load, or evidence of oil and coolant mixing (milky oil, oily coolant). Any internal engine or turbo failure that sends debris through the oil system is also a strong reason to replace the cooler.
Is this cooler genuine Cummins or an aftermarket replacement?
This is a genuine Cummins part, number 3975818, sourced for OEM-level fit, finish, and reliability. Using authentic Cummins components helps ensure proper heat rejection and long-term durability compared to generic aftermarket coolers.
