16098 CWNFA Customer Advisory Letter. The letter is to reinforce the need to annually inspect the aft to aft tank flex line and the midship to aft tank flex line. Over time, a leak may occur by exposure to environmental elements and their corrosive effect on these lines. Additionally, if the lines are damaged due to hard contact with the park brake cable and/or external impact, a leak may occur. In such cases, the lines may show evidence of a jacket cut, nick, or rub-through. If this condition affects your vehicle, at fuel fill-up or start-up, you may notice a CNG odor or hear a hissing sound. If the line experiences an abrupt failure, you may hear a loud bang due to the rapid release of the gas. To check for this condition, please have a certified CNG technician inspect these lines in accordance with GM Service Information procedures for CNG leakage, corrosion and damage. This inspection should be performed annually as part of routine maintenance.
