Product Description
Cummins 3915787 — Threaded Plug (Oil Filter Housing / Oil Pressure Relief)
MPN: 3915787 | Also Known As: threaded plug, pressure relief spring plug, oil filter housing plug | Cross-Ref/Related: 3912618
Why This Part
- ✓ OE sealing plug for the oil system—used in filter housing/pressure relief circuits.
- ✓ Direct-fit for 5.9L B-Series applications listed below (verify by VIN/ESN).
- ✓ Helps restore correct oil pressure after service or component replacement.
- ✓ Durable OE metallurgy and threads for long service life.
Quick Specs
| Type | Threaded oil system plug (filter housing / pressure relief) |
|---|---|
| OE Part # | 3915787 (related: 3912618) |
| Qty Required | Varies by engine configuration; sold individually |
| Typical Location | Oil filter head / oil pressure relief spring bore |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1994–1998 | 5.9L Cummins 12-Valve (B-Series) | Ram 2500/3500 |
| 1998.5–2002 | 5.9L Cummins 24-Valve (ISB) | Ram 2500/3500 |
Industrial/Off-Highway: Used widely on non-certified B-Series and in oil cooler/lube oil sub-assemblies across 4B/6B/ISB families—verify by ESN before ordering.
Often Paired With
- Oil Pressure Relief Components (’98.5–’02 24V): Plunger 3918428, Spring 3925009, O-Ring 3929457, Relief Valve 3936365
- Oil Filter Housing Service (’94–’98 12V): Inspect housing and seals; replace damaged parts
- Fresh oil & filter after any oil system repairs
What’s In The Box
- (1) Genuine Cummins Threaded Plug (3915787)
- Associated seals/hardware sold separately (see “Often Paired With”).
Install Tips
- Clean bore and threads; inspect mating surfaces for burrs or damage.
- Use correct sealant where specified by service manual; torque to OE spec.
- Verify oil pressure after installation; check for seepage on warm-up.
FAQ
WILL THIS FIT MY 1994–2002 5.9L CUMMINS RAM?Yes—this OE plug is used on 12-valve (’94–’98) filter housings and as the pressure-relief spring plug on many 24-valve (’98.5–’02) ISB engines. Always confirm by VIN/ESN.
IS THIS THE PRESSURE RELIEF SPRING PLUG?On many 24-valve ISB applications, yes—3915787 is the plug that retains the oil pressure relief spring and components in the housing.
DOES THIS INCLUDE THE O-RING OR SPRING?No—those parts are separate. Common companions are O-ring 3929457, spring 3925009, plunger 3918428, and relief valve 3936365 (verify by ESN).
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3915787 for proper fit, sealing, and durability.
WHAT OTHER NUMBER IS THIS KNOWN BY?Some catalogs cross-reference 3912618; order by 3915787 for the current OE plug.
