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Westport 15L Engine

Featuring First Generation Westport™ HPDI Technology

Westport 15L Engine

The information contained on this page is for archival purposes only. The Westport 15L engine is no longer sold, but is still fully supported for the life of the product's warranty.

The Westport 15L natural gas engine provided class-leading emissions and performance by maintaining the same horsepower and torque as a diesel-fueled engine. The union of first generation Westport high-pressure direct injection (Westport HPDI) natural gas technology with the proven Cummins ISX long block, provided operators with power & torque required for hauling North America's heaviest loads—GCW 80,000 lbs and over.

Engine Models and Ratings

 (click to view curves)
Advertised Power 475 hp 450 hp 400 hp
Peak Torque (@ 1,200 rpm) 1,750 lb-ft 1,650 lb-ft 1,450 lb-ft


* depending on LNG tank configuration.

Displacement 915 in3 15 L
Advertised Power 400–475 hp 298–354 kW
Peak Torque 1,450–1,750 lb-ft 1,966–2,373 N·m
Governed Speed 2,100–2,200 rpm
Type compression-ignited, inline 6-cylinder
Combustion 1st Generation Westport HPDI
Oil System Capacity 14 U.S. gal 52.9 L
Coolant Capacity* 0.89–1.87 U.S. gal 3.37–7.05 L
Dry Weight 3,111 lbs 1,411 kg
LNG System Weight* +300–1,800 lbs +136–816 kg
Fuel Types LNG (primary) + diesel (pilot ignition)
Aftertreatment Retains OEM DPF and SCR systems

Typical Maintenance Intervals

(whichever comes first)
maintenance items
  1. or as per local regulations
  2. or as specified by OEM maintenance schedule
  3. if applicable
4 months Conduct gas detection system function test1
12 months
1,000 hours
31,250 miles
(50,300 km)
Conduct detailed gas leak check1
Conduct detailed diesel leak check
Replace primary (low pressure) diesel filter2
Drain vent stack filter2
3 years
36,000 miles
(58,000 km)
Inspect CNG accumulator1,2
4,000 hours
125,000 miles
(201,200 km)
Inspect all fluid hoses for leaks and deterioration2
Replace hydraulic spin-on filter2
Replace high pressure natural gas filter2
Replace diesel pump drive belt
Replace aftertreatment diesel dosing pump filter2,3
Replace vent stack filter2
4,500 hours
150,000 miles
(241,000 km)
Clean aftertreament fuel injector3
4,500 hours
200,000 miles
(320,000 km)
Change aftertreatment diesel exhaust fluid dosing unit filter3
5,000 hours
150,000 miles
(240,000 km)
LNG pump maintenance (single tank system)
8,000 hours
250,000 miles
(402,300 km)
LNG pump maintenance (dual tank system)


The Westport warranty covers the base engine, on-engine fuel system, and LNG fuel tank modules.

  (whichever occurs first)
Base Warranty 250,000 mi (400,000 km) 2 6,250
Extended Warranty 500,000 mi (800,000 km) 5 12,500