Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 55 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTS - 2.2L)FUEL SYSTEMS (CNG)FUEL TANK CLEANING (CNG)
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6
Fuel Tank Cleaning (CNG)
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Fuel Tank Cleaning (CNG)
WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Tank cleaning is only necessary when a part such as the High Pressure Lock-Off (HPL) solenoid has failed due to fuel contamination or when excess water accumulation, that may reduce fuel capacity, is suspected within the tank.
- Perform the Fuel Pressure Relief Procedure. See FUEL SYSTEM PRESSURE RELEASE (CNG) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
- Perform the Fuel Tank Venting Procedure. See FUEL TANK VENTING (CNG) under FUELS SYSTEMS (CNG) in REMOVAL & INSTALLATION - CAVALIER & SUNFIRE article.
- Perform the High Pressure Lock-Off (HPL) solenoid removal procedure leaving the HPL installed into the tank finger-tight. See HIGH PRESSURE LOCK-OFF SOLENOID under FUEL SYSTEMS (CNG) in REMOVAL & INSTALLATION - CAVALIER & SUNFIRE article.
- Place the CNG Tank Support Harness (J 44244), or equivalent, on the shop floor.
- Lower the CNG fuel tank on top of the CNG Tank Support Harness.
- Place the CNG Tank Support Harness support flap so that the HPL protrudes through the flap.
- Place the CNG Tank Support Harness straps around the CNG fuel tank placing the end strap over the HPL and around the neck of the CNG fuel tank.
- Securely fasten the CNG Tank Support Harness straps around the CNG fuel tank. Longer CNG fuel tanks will require the use of all the CNG Tank Support Harness straps.
- Connect the CNG Tank Support Harness to a suitable lifting device.
- Slowly raise the CNG fuel tank until the HPL is several inches above the ground ensuring that the HPL does not contact the floor during the lifting process.
- Place a container underneath the HPL to collect any drained fluids.
- Remove the HPL, allowing any fluids to drain completely from the CNG fuel tank.
- Dispose of any collected fluids in a safe and approved manner.
- Flush the inside of the CNG fuel tank using clean water.
- Dry the inside of the CNG fuel tank using compressed air.
- Install the HPL finger-tight.
- Slowly lower the CNG fuel tank back to the ground ensuring the HPL does not contact the ground.
- Remove the CNG Tank Support Harness from the CNG fuel tank.
- Complete the installation of the HPL into the tank and the tank into the vehicle by completing the installation steps as indicated in the High Pressure Lock-Off (HPL) Solenoid Replacement. See HIGH PRESSURE LOCK-OFF SOLENOID under FUEL SYSTEMS (CNG) in REMOVAL & INSTALLATION - CAVALIER & SUNFIRE article.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.