User Guidelines

Cummins Westport provides recommended use and maintenance guidelines on our products to help guide customers and dealers on developing vehicle specifications to meet your performance, reliability, and durability expectations. Failure to follow our recommended use, maintenance, or operating guidelines may lead to diminished performance, reliability, or durability.  

In general, for on highway applications less than 60,000 miles per year and up to 66,000 lb. GVW, the L9N is an excellent choice.  

For on highway vehicles operating more than 60,000 miles per year, over 66,000 lb GVW and up to 80,000 lb. GVW, regardless of application, the ISX12N is recommended.

Cummins Westport does not grant waivers or exceptions for operation outside Intended Use Guidelines. Customers, dealers, and OEMs should be advised that applications outside these guidelines can result in some negative consequences, degraded performance, or reduced engine life. Engine damage directly attributable to operating in excess of intended use guidelines may not be eligible for applicable coverage.  

See the Intended Use Guidelines Bulletin and Natural Gas Driver Tips card for information.