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HSChapter 84
U.S. imports of parts for compression-ignition (diesel) internal combustion piston engines (non-aircraft) (HS 840999) totaled $353.1M in May 2026, traded with 92 countries.
Importers of Parts for Compression-Ignition (Diesel) Internal Combustion Piston Engines (Non-Aircraft) paid $43.0M in duties in May 2026 — an effective duty rate of 17% on $259.8M in dutiable value, based on actual customs collections rather than the published tariff schedule. Parts for Compression-Ignition (Diesel) Internal Combustion Piston Engines (Non-Aircraft) imports of $353.1M in May 2026 ran 12% above the year-to-date monthly average of $316.3M.
Last updated: May 2026 dataServing the heavy-duty diesel aftermarket and OEM supply chains, this heading covers components — cast-iron pistons, connecting rods, and general parts — for diesel engines used in road vehicles, marine propulsion, and other applications. Mexico and Germany lead US imports, reflecting both nearshore automotive manufacturing and Germany's strong position in commercial-vehicle diesel technology. China is also a significant source, making Section 301 tariff exposure a live concern for procurement teams sourcing diesel parts across multiple origins. The schedule's end-use tiers (road, marine, NESOI) mirror those for spark-ignition parts under 840991, so consistent classification methodology across both headings is important for importers handling mixed engine-parts shipments.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
Lines such as 8409994000 are reserved for parts specifically designed for diesel engines powering road tractors, buses, automobiles, and trucks. Parts for stationary power generation, agricultural equipment, or other non-road, non-marine applications fall into the residual NESOI line (8409998000). The end-use of the engine — not the part in isolation — governs which line applies.
Origin matters significantly here. Parts from China may carry Section 301 additional duties, while parts from Mexico may qualify for preferential treatment under USMCA if they meet applicable rules of origin. Germany-origin parts enter under standard MFN rates without a preferential program currently in force between the US and the EU. Importers should conduct an origin analysis for each supplier before committing to a sourcing strategy.
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Monthly import values over time
HS10 import codes under this HS6 parent. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 8409999190 | PARTS FR COMP-IG PST ENG FR RD TR,BUS,AUTO,TRUCKS | $160.9M | 24.65% | 89.19% | $39.7M |
| 8409999990 | PARTS FOR COMP-IG INT COMB PST ENGINES, NESOI | $108.3M | 16.97% | 76.55% | $18.4M |
| 8409991040 | CST TRN F COMP-IG PST ENG FOR RD TR,BUS,AUTO,TRUCK | $17.3M | 24.54% | 97.52% | $4.2M |
| 8409999110 | CONN RODS FOR COMP-IG PST ENG FR RD TR,BUS,AUTO,TK | $15.0M | 10.61% | 43.79% | $1.6M |
| 8409991080 | CAST-IRON PST FOR COMP-IGNITION PST ENG, NESOI | $11.2M | 17.25% | 95.11% | $1.9M |
| 8409999290 | PARTS FOR COMP-IG INT COMB PST ENG FOR MARINE PROP | $8.9M | 12.84% | 78.22% | $1.1M |
| 8409999910 | CONN RODS FOR COMP-IG INT COMB PST ENG, NESOI | $6.4M | 14.20% | 89.60% | $911K |
| 8409991060 | CAST-IRON PST FOR COMP-IGNITION PST ENG FOR MARINE | $708K | 3.60% | 35.99% | $25K |
| 8409999210 | CONN RODS FOR COMP-IG PST ENG FOR MARINE PROPULSN | $192K | 12.50% | 100.00% | $24K |
PARTS FR COMP-IG PST ENG FR RD TR,BUS,AUTO,TRUCKS
PARTS FOR COMP-IG INT COMB PST ENGINES, NESOI
CST TRN F COMP-IG PST ENG FOR RD TR,BUS,AUTO,TRUCK
CONN RODS FOR COMP-IG PST ENG FR RD TR,BUS,AUTO,TK
CAST-IRON PST FOR COMP-IGNITION PST ENG, NESOI
PARTS FOR COMP-IG INT COMB PST ENG FOR MARINE PROP
CONN RODS FOR COMP-IG INT COMB PST ENG, NESOI
CAST-IRON PST FOR COMP-IGNITION PST ENG FOR MARINE
CONN RODS FOR COMP-IG PST ENG FOR MARINE PROPULSN
HS10 export codes under this HS6 parent. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 8409994000 | PARTS F DIESEL ENG F ROAD TR, BUS, AUTO, TRUCK | $99.7M |
| 8409998000 | PARTS FOR DIESEL ENGINES, NESOI | $98.3M |
| 8409996000 | PARTS FOR DIESEL ENGINES FOR MARINE PROPULSION | $15.8M |
PARTS F DIESEL ENG F ROAD TR, BUS, AUTO, TRUCK
3.7M kg
PARTS FOR DIESEL ENGINES, NESOI
3.0M kg
PARTS FOR DIESEL ENGINES FOR MARINE PROPULSION
138.2K kg
TURBOJET AND TURBOPROLLER PARTS
HS 841191
| Port | Imports | Exports | Balance |
|---|---|---|---|
| LAREDO, TX | $75.1M | $24.5M | -$50.6M |
| NEWARK, NJ | $39.3M | $3.7M | -$35.6M |
| NORFOLK-NEWPORT NEWS, VA | $33.3M | $8.7M | -$24.6M |