GM Service Manual Online
For 1990-2009 cars only

Important: Use compressed natural gas (CNG) that meets the specifications of SAE J1616. These specifications place limits on particulate contamination and moisture content. CNG that meets these specifications provides improved driveability and emission control system performance. CNG that does not meet these specifications may cause fuel system or engine damage. If your GM dealer determines that the cause of the condition is the type of CNG used, repairs may not be covered under warranty.

This schedule information is supplemental to the gasoline service manual information. Refer to the G/H van Service Manual for additional maintenance items.

The services shown in this schedule up to 100 000 km (60,000 miles) should be performed after 100 000 km (60,000 miles) at the same intervals.

Every 12 500 km (7,500 Miles)

    • Inspect the CNG fuel lines and the fittings for leaks.
    • Inspect the CNG fill valve O-ring.
    • Inspect the CNG fill valve filter.

Every 100 000 km (60,000 Miles)

    • Remove and clean the CNG fill valve filter.
    • Replace the in-line CNG filter.
    • Replace the spark plugs.
    • Inspect the spark plug wires.