Product Description
Cummins 3900068 — Ring Dowel, 14 mm (Cylinder Head / Main Bearing Cap Alignment)
MPN: 3900068 | Also Known As: dowel ring, locating sleeve, ring dowel | Size: 14 mm | Cross-Refs: Interstate-McBee M-3900068; 499187
Why This Part
- ✓ Precision alignment for cylinder head-to-block or main bearing cap locations.
- ✓ Prevents fretting and cap/head walk to protect sealing and torque retention.
- ✓ Direct-fit OE geometry for Cummins B-Series (5.9L/6.7L) applications.
- ✓ Hardened steel construction for long service life.
Quick Specs
| Type | Ring Dowel (locating sleeve) for alignment |
|---|---|
| Diameter | 14 mm |
| OE Part # | 3900068 |
| Cross-References | M-3900068 (Interstate-McBee); 499187 |
| Quantity | Sold individually; quantity varies by location (see FAQ) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–2002 | 5.9L Cummins (12V/24V B-Series) | Ram 2500/3500 |
| 2003–2018 | 5.9L / 6.7L Cummins ISB (Common-Rail) | Ram 2500/3500 |
Notes: Also used across 4B/6B industrial and ISB/QSB variants. Because dowels are used in multiple locations, verify by ESN and service manual for exact positions and quantities.
Often Paired With
- Cylinder Head Gasket Set (when servicing the head)
- Head Bolts/Studs (ARP or OE) after head work
- Main Bearing Set & Main Cap Bolts (bottom-end jobs)
What’s In The Box
- (1) Genuine Cummins Ring Dowel (3900068), 14 mm
Install Tips
- Match dowel size/seat depth to the service location (head or main cap).
- Lightly oil on install; do not force a distorted dowel—replace instead.
- Follow the Cummins torque sequence/specs for the mated components.
FAQ
WHERE IS 3900068 USED—CYLINDER HEAD OR MAIN BEARING CAP?Both. It’s a 14 mm OE ring dowel commonly used for cylinder head alignment and also as a main bearing cap locating dowel on B-Series/ISB engines. Verify your exact location by ESN/service manual.
HOW MANY DO I NEED?Quantity varies by job. Head alignment typically uses dowels at the deck; main bearing caps may also be dowel-located. Order the number required for the location(s) you are servicing.
WHAT YEARS/TRUCKS DOES THIS COVER?Broadly used across 1989–2018 5.9L/6.7L Ram and other B-Series/ISB applications. Always confirm by VIN/ESN.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3900068. Aftermarket equivalents include Interstate-McBee M-3900068.
WHAT SIZE IS THE DOWEL?14 mm ring dowel.
