A common problem on the Duramax LLY engine is contamination of the fuel fittings resulting in injector failure when serviced. Corrosion can form between the line and injector nut and fall into the injector when the line is removed or installed. Replacing the line at time of injector replacement or service is highly recommended to reduce injector failure due to contamination. GB premium fuel lines meet or exceed critical OE performance specifications for sealing and burst pressure.