Product Description
Cummins 3902343 — Genuine Cylinder Head Alignment Dowel (Ring Dowel)
MPN: 3902343 | Also Known As: ring dowel, head alignment dowel | Position: Inserts in the engine block to locate the cylinder head
The genuine Cummins 3902343 alignment dowel precisely locates the cylinder head on the block for accurate gasket crush and long-term sealing. Cataloged for the B-Series 5.9L and widely sold for 1989–2018 5.9L & 6.7L applications, this OE “ring dowel” ensures the head seats squarely—critical for successful head-gasket service or engine assembly. Most engines use two; order accordingly.
Features & Benefits
- OE locating accuracy to keep the head perfectly aligned during torque sequence.
- Prevents gasket shift and uneven clamp load that can lead to premature leaks.
- Hardened steel construction for repeatable installs and durability.
- Direct-fit for B-Series/ISB engines—no modification required.
Verified Fitment (Automotive)
| Year Range | Engine | Notes |
|---|---|---|
| 1989–1993 | 5.9L 12V (VE) | D/W 250 & 350 — typically 2 required |
| 1994–1998 | 5.9L 12V (P7100) | Ram 2500/3500 — 2 required |
| 1998.5–2002 | 5.9L 24V (VP44) | Ram 2500/3500 — 2 required |
| 2003–2007 | 5.9L ISB (Common-Rail) | Ram 2500/3500 — 2 required |
| 2007.5–2018 | 6.7L ISB | Ram 2500/3500/4500/5500 — 2 required |
Catalog context: Cummins lists 3902343 as a Ring Dowel used primarily on 5.9L B-engines. Multiple diesel retailers sell this same dowel for 1989–2018 5.9L & 6.7L Ram coverage. For industrial/off-highway engines, verify by ESN before ordering.
Specifications
- Type: Cylinder head alignment dowel (ring dowel)
- OE Part Number: 3902343
- Location: Press-fits into block deck (head registers on dowels)
- Material: Hardened steel
- Quantity Required: Typically 2 per engine (sold individually)
Often Paired With
- Head gasket & upper gasket set (match to engine year)
- Head bolts or studs (replace torque-to-yield hardware as required)
- Coolant & oil (service fluids after major head work)
- Head locating/installer tools (to guide the head over new dowels)
What’s In The Box
- (1) Genuine Cummins Cylinder Head Alignment Dowel (3902343)
Installation Tips
- Confirm the block bores are clean and burr-free; lightly oil before seating the dowel.
- Install two dowels in the block deck, then carefully lower the head squarely over them.
- Follow the OE torque pattern/angles for your head bolts or studs; recheck final torque after the first heat cycle if your fastener kit requires it.
FAQ
HOW MANY DOWELS DOES MY ENGINE NEED?
Most 5.9L/6.7L applications use two alignment dowels—order individually as needed.
WILL THIS FIT BOTH 5.9L AND 6.7L ENGINES?
Yes—diesel retailers list 3902343 for 1989–2018 5.9L & 6.7L engines. Cummins catalogs it as a ring dowel for B-series; verify by VIN/ESN for industrial engines.
WHERE DO THESE INSTALL?
Into the engine block at the deck surface; they locate the cylinder head during installation.
CAN I REUSE OLD DOWELS?
If damaged, corroded, or loose in the block, replace them. Fresh dowels help ensure precise alignment and sealing.
IS THIS A GENUINE CUMMINS PART?
Yes—OE Cummins 3902343.
