Cummins-Compatible Cylinder Liner Sleeve 3904166 – Model-Matched

Cross-reference verified — Every 3904166 variant matched against engine serial and CM code before dispatch, so the liner fits the exact block it ships to.

Technical Specifications

Application Suitability

Why the Same Part Number Ships in Several Variants

A single Cylinder Liner 3904166 for Cummins engine cross reference can map to blocks with different flange steps, wall thicknesses, or protrusion requirements depending on the CM code. The part number alone does not guarantee fitment across every variant in the B, ISB, and QSB families.

I once supported a customer who ordered by 3904166 for a Cummins ISB6.7 build. The liner arrived, the technician pressed it in, and the engine leaked coolant within the first run. The CM code on that specific serial number called for a different flange step height than the base 3904166 spec. Cross-reference tables copied between sellers often collapse these variants into one row, which means the buyer inherits every mistake the table ever accumulated [NEED_CITE: Cummins service bulletin on cylinder liner variant identification by ESN]. The consequence is not just a return shipment — the block bore may already be scored from the misfit press, adding machining cost to an already delayed repair.

Fitment Scope Across Engine Generations

The Cylinder Liner 3904166 for Cummins engine cross reference spans from early 4B3.9 and 6B5.9 blocks through ISB, ISBE, and QSB variants, but each generation shifted internal dimensions slightly. A liner that seals correctly in a B5.9-C industrial engine may sit too high or too low in a QSB6.7 CM2250 block. Verifying the engine serial number narrows the match to one definitive liner profile, eliminating the trial-fitment gamble that costs machine hours on site.

Cross-Reference Verification Between Standard and Oversize

The reference numbers DS-3904166 and DS3904166 typically point to the standard bore size, while DS-3904166OS and DS3904166OS indicate oversize variants intended for blocks that have already been rebored during a previous rebuild. Installing a standard-size liner in a block that was already machined to oversize creates an interference gap, leading to coolant seepage and poor heat transfer [NEED_CITE: cylinder liner interference fit standards for medium-duty diesel engines]. Confirming whether the block is on its first build or a subsequent overhaul determines which variant the order should carry.

Dimensional Checks That Decide Whether the Liner Seats

Three measurements matter most when matching a Cylinder Liner 3904166 for Cummins engine cross reference to a specific block: outer diameter at the flange seat, flange step height relative to the block deck, and liner protrusion above the deck surface. If protrusion is outside the engine manual's tolerance band, head gasket compression becomes uneven, and the gasket fails prematurely. These are not catalog-level details — they require comparing the incoming liner against the block's machined dimensions, which is why sample-before-bulk ordering exists for buyers who cannot risk a misfit across a fleet overhaul.

The Cost of Skipping Variant Confirmation

When a liner is forced into a block with a mismatched flange step, the immediate symptom is often a coolant leak at the liner-to-block interface. The hidden cost is the secondary damage: scored bore surfaces, contaminated lubrication passages, and in some cases a warped head from uneven thermal loading [NEED_CITE: failure analysis of diesel engine cylinder liner misfit consequences]. The machine does not just wait for a replacement liner — it waits for block inspection, possible line-boring, and a full reseal of the upper engine, stretching a single-day swap into a multi-week event.

How Fitment Gets Confirmed Before Dispatch

Identification starts from whatever the buyer has: a part number, an engine model, a serial number, or a photograph of the worn liner and its nameplate. Our technical team checks the submitted data against the block casting and CM code to confirm which 3904166 variant applies. Both our own production lines and qualified sourced supply carry the same warranty terms, so a single account covers all liner variants across the B through QSB range. We support orders from one piece for an emergency press, and sample units ship ahead of bulk commitments so the workshop can verify fitment before the full consignment leaves Guangzhou. Cross-reference verification covers superseded and alternate numbers, so a worn tag with a discontinued reference still resolves to the correct current liner.

Documentation & Verification

• Commercial invoice listing each liner variant and corresponding engine serial range
• Cross-reference sheet mapping 3904166 to DS-3904166 and OS variants (reference only)
• Dimensional inspection record covering outer diameter, flange step, and protrusion
• Warranty terms covering manufacturing defects for 3 to 12 months
• Packing photographs showing liner protection before crate closure
• HS code and customs documentation support for international shipment

Fitment Check Before Installation

• Compare incoming liner outer diameter against the block bore with a micrometer before pressing
• Verify flange step height matches the block deck specification for the specific CM code
• Check liner protrusion with a dial indicator once seated to confirm it falls within tolerance
• Inspect the liner bore surface for any transit scoring that could compromise piston ring sealing
• If the block has prior overhaul history, confirm whether oversize DS-3904166OS is required instead of standard

Requesting an Accurate Fitment Match

Send the engine model, serial number, and any visible CM code from the nameplate, and the technical team will return the confirmed liner variant along with the applicable cross-reference. If the nameplate is worn or painted over, a clear photograph of the old liner and the block casting number is usually sufficient to narrow the match. For fleet orders covering multiple engine builds, a list of serial numbers lets us flag any variant splits before the order ships.

Frequently Asked Questions

Q: How do I confirm 3904166 fits my specific Cummins CM code? A: Provide the full engine model and serial number. Our technical team cross-references the ESN against block casting records to verify flange step height, wall thickness, and protrusion spec for that exact build. CM codes like CM550, CM850, CM2150, and CM2250 can each call for a different liner profile under the same base number, so serial-level confirmation eliminates guesswork and avoids a misfit on the bench.

Q: What is the difference between DS-3904166 and DS-3904166OS? A: DS-3904166 is the standard bore liner for first-build or untouched blocks. The OS suffix indicates an oversize variant for blocks that have been rebored during a prior overhaul. Installing a standard liner in an already-rebored block leaves an interference gap that causes coolant leaks and poor heat transfer. Confirming the block's machining history determines which variant you need.

Q: The nameplate is gone and only the engine model is visible — can you still identify the liner? A: Yes. A photograph of the old liner, any remaining casting marks on the block, and the engine model allow our team to narrow the variant. We compare physical dimensions from your photos against known profiles for that model family. In cases where two variants remain possible, we ship a sample unit for fitment confirmation before releasing the full order.

Q: Why do different sellers list different cross-references for the same base number? A: Cross-reference tables are often copied between listings without verification against current engineering revisions. Superseded numbers, regional variants, and oversize designations get mixed into a single row. We verify each reference number against the engine serial and CM code independently, so the cross-reference you receive is specific to your build rather than a generic compilation.

Q: Can I order a single sample before committing to a bulk purchase? A: Yes, the minimum order is one piece. A sample liner lets your workshop press-fit and measure protrusion in the actual block before the remaining units ship. This is especially useful when the fleet contains engines from different production runs where variant splits are possible. The sample carries the same warranty terms as any production order.