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)

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.