Fuel Tank Inspection (In-Vehicle)

WARNING: This page is about a different car, the 2002 Ford Pickup and 2002 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The following procedure is an in-vehicle visual inspection for natural gas fuel cylinders. A one year, 12,000-mile (whichever occurs first) inspection interval is assumed.

Raise and support vehicle. Examine vehicle underbody and chassis in general area near fuel tank(s) for any indication of collision damage, malfunction, fire or excessive mud/dirt accumulation. Examine fuel tank stone/heat shield for any indication of collision damage, malfunction, fire or excessive mud/dirt accumulation. Remove fuel tank stone/heat shield. Examine fuel tank(s) and stone/heat shield interior for any foreign objects (such as stones or gravel) or foreign materials (such as mud, salt, liquids or chemical residue).
Remove any foreign material, using only a clean, dry cloth. Remove all foreign objects. DO NOT use water or any cleaners. Examine fuel tank labels for tank expiration date. Use a light and mirror to access labels hidden from normal view. If expiration date has been exceeded, condemn tank, using procedures in step 8.

NOTE: Compressed Natural Gas Pamphlet C6.2 can be obtained from Compressed Gas Association, Inc., 1725 Jefferson Davis Highway, Arlington, VA 22202-4102.

Inspect tank sidewall and dome ends, following general guidelines set forth in Compressed Gas Association Pamphlet C6.2. Inspect tank(s) for abrasions, dents, cracking, blistering or peeling of clear coating, corrosion, cracks or gouges in metal dome, cracks in fiberglass overwrap, impact damage (cracking) in fiberglass overwrap, cuts or gouges in fiberglass overwrap, exposed fibers, delamination (separating) of fiberglass overwrap, discoloration of fiberglass overwrap, and/or fire or heat damage, such as charring or discoloration.
If any flaws are detected, measure depth and length of flaw in accordance with Compressed Gas Association Pamphlet C6.2 guidelines. If any of the flaws cannot be completely measured in vehicle, tank must be removed from vehicle for further inspection. If tanks have been or are suspected of having been exposed to a corrosive chemical spill, tank must be removed from vehicle for further inspection of complete composite surface, including area under tank straps. If there is any indication of chemical attack, such as blistering, cracking or delamination, tanks must be condemned and replaced with new tanks.
The acceptance criteria for cuts and abrasions are different from those listed in Section 6.5.1 of Compressed Gas Association Pamphlet C6.2. These tanks have extra epoxy resin and a clear coat to reduce sensitivity to surface damage. The following are composite wrap inspection criteria:
- Level 1 Abrasions
  
  These are defined as minor abrasions, such as scuffs less than .010" (0.254 mm) deep, and are acceptable without repair.
- Level 2 Abrasions
  
  These are defined as abrasions having some exposed fibers or flat spots with a depth between .010-.030" (.254-.762 mm). Level 2 abrasions must be repaired before tank is returned to service.
- Level 1 Cuts
  
  These are defined as cuts or scratches less than .010" (.254 mm) deep and are acceptable without repair regardless of length, number or direction.
- Level 2 Cuts
  
  These cuts have a maximum depth of .030" (.762 mm) and a maximum length of 8" (203 mm). Level 2 cuts must be repaired before tank is returned to service.
Repair damage to composite wrap as follows:
- Level 2 cuts and abrasions are to be coated with epoxy resin. Mix and apply commercial room temperature cure, 2-component epoxy resin according to manufacturer's instructions. Frayed fibers must be cut away before application of epoxy resin.
- Tanks with damage exceeding Level 2 must be condemned using procedures in step 8.
- The criteria for other damage to composite wrap are defined in Compressed Gas Association Pamphlet C6.2.
The metal tank ends are protected with a multi-coat system using epoxy and polyurethane coatings. Chips in coating must be evaluated and repaired. Metal tank end external inspection criteria are as follows:
- Level 1 Chips
  
  These are chips or abrasions which do not penetrate black epoxy coating. The steel or gray primer has not been exposed. Level 1 chips require no repair.
- Level 2 Chips
  
  These are chips or abrasions which penetrate black epoxy coating and must be repaired as follows to prevent corrosion:
  1. Sand damaged area to remove rust and rough up surrounding coating.
  2. Clean damaged area with a commercial pre-paint cleaning solvent.
  3. Apply a zinc-rich, cold galvanizing compound (Rust-Oleum™ Zinc-Rich or equivalent commercial product).
- Dents
  
  Tanks with dents to metal ends which are more than .060" (1.524 mm) in depth must be removed from service and condemned using procedures in step 8.
- Gouges
  
  Tanks with sharp gouges penetrating coating and into metal liner must be removed from service and condemned using procedures in step 8.
Condemned tanks, whether due to damage or expiration, shall be removed from vehicle and destroyed as follows:
1. Vent and remove fuel tanks. See FUEL SYSTEM PRESSURE RELEASE and FUEL TANK under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.
2. Remove fuel tank solenoid valve. See FUEL TANK SHUTOFF SOLENOID VALVE under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL.
3. Purge fuel tank with compressed air for 30 seconds.
4. Destroy fuel tank by drilling a .50" (12.7 mm) diameter hole in fuel tank sidewall.
Examine fuel tank straps for correct positioning of rubber isolators. Replace rubber isolators as necessary. When completed, record date, vehicle mileage and results of fuel tank inspection.