Product Description
If your Cummins 5.9L 12-valve (1994–1998) engine isn’t reaching optimal operating temperature or you’re seeing erratic gauge behavior, the genuine Cummins 3934373 180° thermostat is your factory-specified solution. This OEM part restores correct thermal regulation and helps protect your engine from long warm-ups or overheating.
Built to Cummins standards, this thermostat drops right in — no modifications, no performance compromise. Whether you’re running a daily driver or building for pulling, rely on the same temperature control the factory designed.
Fitment Details
- Fits 1994–1998 Ram 2500/3500 with 5.9L Cummins 12-valve engine (P7100 injection pump).
- Designed specifically for the Cummins B-series diesel engine; also used in industrial/ off-highway versions — verify ESN for non-automotive use.
- One thermostat required per engine. Housing gaskets and O-rings sold separately.
Why Choose This OEM Thermostat?
- Maintains accurate 180° F (≈82 °C) opening — restores factory thermal profile.
- Helps reduce frequent temperature gauge cycling and supports proper heater performance in colder climates.
- Direct-fit Cummins genuine part — engineered for durability, backed by the factory warranty.
Cross Reference / Alternatives
When you’re servicing the cooling system in your 5.9L Cummins, you may also consider these related genuine parts:
- CUMMINS 3925466 OEM THERMOSTAT O-RING – 5.9L CUMMINS (1994-1998)
- CUMMINS 3933325 OEM THERMOSTAT HOUSING GASKET – 5.9L CUMMINS (1994-1998)
- CUMMINS 3927305 OEM THERMOSTAT HOUSING GASKET – Alternate for 5.9L CUMMINS (1994-1998)
FAQ
Will this thermostat fit my 1994-1998 5.9L Cummins engine?
Yes — it fits Ram 2500/3500 trucks from 1994 to 1998 with the 5.9L 12-valve engine. Confirm your ESN/engine type for non-truck or industrial applications.
What seals or gaskets do I need with the thermostat?
You’ll typically pair it with O-ring part 3925466 and housing gasket 3933325 or 3927305 — verify which your vehicle uses.
Why choose the 3934373 instead of older thermostat numbers?
The 3934373 was introduced by Cummins to reduce temperature gauge cycling on some ’94–’98 trucks while maintaining the 180° spec.
Is this a genuine Cummins part?
Yes — this is an OEM Cummins-branded thermostat (part 3934373).
| Specifications for CUMMINS 3934373 | |
|---|---|
| Part Number | 3934373 |
| Brand | Cummins |
| Application | 5.9L Cummins 12-valve (1994-1998 Ram 2500/3500 & B-Series) |
| Function | 180° F coolant thermostat – controls engine warm-up & operating temp |
| GTIN | – (not publicly listed) |
| UPC | – (not publicly listed) |
| E-Codes / Emissions | Not applicable |
| Shipping Info | Approx weight 0.25 lbs (per Cummins shop site) |
| Prop 65 Warning | WARNING: This product can expose you to chemicals known to the State of California to cause cancer, birth defects or other reproductive harm. For more info visit P65Warnings.ca.gov |
| Cross Reference | See related Cummins housing gasket 3933325, O-ring 3925466 |
