Product Description
Cummins 3927948 — Genuine 12mm Main Bearing Cap Bolt for 5.9L/6.7L
MPN: 3927948 | Also Known As: main cap bolt, main bearing bolt, fracture-resistant screw | Thread/Size: M12 x 1.50 x 119 mm
Genuine Cummins main bearing cap bolt engineered to clamp the crankshaft main caps with OE strength and consistency. Ideal for stock rebuilds and performance refreshes. Sold individually; 14 required per 5.9L/6.7L engine (10 for 4BT).
Features & Benefits
- OE metallurgy and finish for reliable clamping under heat and load.
- Precision thread and under-head geometry for accurate torque/angle.
- Direct-fit replacement for ISB 5.9L and 6.7L main cap fasteners.
- Service-bay friendly: replace during any bottom-end rebuild to avoid mixed hardware.
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1998.5–2002 | Ram 5.9L ISB (24V VP44) | Ram 2500/3500 |
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
| 2007.5–2018 | Ram 6.7L ISB (24V Common-Rail) | Ram 2500/3500 |
Industrial/Off-Highway: 4BT/6BT/ISB/QSB applications that use 12 mm main bolts — verify by ESN before ordering.
Compatibility Notes:
- Quantity per engine: 14 for 5.9L/6.7L inline-6; 10 for 4BT inline-4.
- Always follow Cummins torque/angle procedure; do not mix new and used fasteners on the same engine.
Specifications
- Type: Main bearing cap bolt (engine bottom-end fastener)
- OE Part Number: 3927948
- Size: M12 x 1.50 x 119 mm
- Quantity Required: 14 per 5.9L/6.7L; 10 per 4BT (sold individually)
Often Paired With
- Main bearing set (OE or performance)
- Rear main seal kit (year/engine specific)
- Assembly lube for bearings and fasteners
What’s In The Box
- (1) Genuine Cummins Main Bearing Cap Bolt (3927948)
Installation Tips
- Clean threads in block and under-head seating surfaces; chase if necessary.
- Lightly oil threads and under-head if specified by service manual; torque/angle to spec in sequence.
- Replace as a set during rebuilds; do not reuse damaged or stretched fasteners.
FAQ
HOW MANY MAIN CAP BOLTS DO I NEED?
For 5.9L/6.7L inline-6 engines you need 14 bolts total; for 4BT inline-4 you need 10 bolts. This item is sold individually.
WILL THIS FIT MY 5.9L OR 6.7L RAM?
Yes—3927948 covers 5.9L (1998.5–2007) and 6.7L (2007.5–2018) ISB applications. Verify by VIN/ESN for absolute accuracy.
ARE THESE REUSABLE?
Best practice is to replace main cap bolts during a rebuild. Always inspect for stretch or damage and follow Cummins’ service guidance.
WHAT IS THE SIZE/SPEC?
M12 x 1.50 thread, 119 mm length. Use the factory torque/angle procedure from the Cummins manual.
IS THIS A GENUINE CUMMINS PART?
Yes—OE Cummins part 3927948 with OEM fit and clamping performance.
