GMC 2016 Silverado Manual page 28

In addition, the CNG system
requires the following every
60 000 km (37,500 mi) or
36 months, whichever occurs first:
Visual inspection of the CNG
fuel tanks by a CSA
International-certified inspector
or authorized GM dealer. For
more information, see your
dealer or see:
http://www.csa-international.org
Warning
The CNG fuel system and tank(s)
must be inspected by a certified
inspector if the vehicle is involved
in a collision or fire.
The fuel tanks must be replaced
15 years after manufacture. The
expiration date of the fuel tanks
is on a label on the fuel tanks.
Have an authorized GM dealer
replace the fuel tanks. Do not
reuse old fuel tanks.
Replacement of the high
pressure CNG filter. See your
dealer.
If there are cuts or corrosion in
the flex line jacket, replace
the line.
Service and Maintenance 27