Westport Confirms Sunset of the 15L Natural Gas Engine

Upon issuing its third-quarter financials last week, Westport Innovations Inc. revealed the discontinuation of its longstanding 15-liter natural gas engine platform.

The Westport 15L – originally marketed as the ISX G – debuted more than a decade ago and has since been integrated into hundreds of the heaviest of heavy-duty trucks. Paired with Westport’s high-pressure direct-injection technology and a liquefied natural gas (LNG) fuel system, the 15-liter engine was among the transportation industry’s initial natural gas success stories. The 15L found its way into platforms such as the Peterbilt 367 and Kenworth T800 tractors, enabling heavy-haul truckers to take advantage of cost-effective natural gas fuel.

Demand for the 15-liter natural gas powerplant did not disappear, even though the numbers of shipments were relatively low in recent quarters. Rather, immense attention has shifted to the 11.9-liter Cummins Westport ISX12 G natural gas engine, which will be offered in configurations up to 400 hp/1450 lb.-ft. of torque.

The 15L met that level of performance at the low end of the spectrum and topped out at 475 hp/1,750 lb.-ft. of torque.

In its third-quarter 2013 announcement, Westport said its ‘production focus is shifting from an upfit model to vertical integration of Westport’s next generation of HPDI for targeted OEMs.’ The 15L has been upfitted into trucks at Westport’s facilities in Vancouver – a model that no longer fits the company’s emphasis.

A Westport representative told NGT News in late September – off the record, at the time – that the company had already informed its major dealer partners about the decision to end North American production of the 15-liter engine, but said that an official announcement was not in the queue.

The representative noted that Westport would likely see a flurry orders for the 15L through October and early November from customers who would quickly execute purchases of the engine upon the news of its discontinuation.

The last day to order the 15L is November 15.


  1. I bought a 2012 Peterbilt 367 with Cummins Westport GX 15 engine. The truck cannot make it to a fuel station running on diesel
    If you fill the tanks with LNG and the truck sits for a week all 200 gallons of the LNG evaporates in thin air so you tow it to a fuel station. That is if the diesel time has not run out. Otherwise you have to call Peterbilt to reset the ECM for another 30 minutes of
    diesel time. This Cost me $360.00 to come to my yard and do it or I’d have to tow it costing a lot more .After the reset the truck will run for three 10 minutes periods on diesel @ a max speed of 6 MPH which could not safely operate on any road or hi-way.At 6 mph you will cause an accident. I called Westport and asked them if the ECM could be set to get up to hi-way speed without any reset at all as you never know how far a refueling station could be. Westport said NO and told me I could buy the reset tool for ove $1,000.00 to reset the ECM and by attending a class in Dallas Tx. for $800.00 . I could do the diesel reset myself.I told them I’d be dumping $2,000.00 and still be doing max 6 mph on diesel and still could not get to a fuel station.This conversion cannot work without some modification to operate as a multi – fuel unit as fueling stations are so far apart, This conversion should never be sold at all. That is why Westport discontinued the engine .Seem like they never talked to an owner or tested the engine on the road. Polution wise it discharges Methane in the atmosphere through its Boil Off Gas which should be illegal. It could be outright dangerous if it shuts down on the Interstate and going 6mph to exit. It does have alarms and monitors to remind you on how much LNG you have and estimated distance. This is useless if there is no fueling station
    within the range . LNG is not available on ever corner yet . You will get held up in traffic and at shippers p/up and del. while your planned trip estimating your fuel and availabilty, the fuel evaporates affecting you estimated distance. For designated 24/7 hauls it might work ok if fuel is available on one end.


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