Fuel Tank Replacement
Fuel Tank ReplacementWARNING: Compressed natural gas is flammable and highly explosive. You could be killed or seriously injured if leaking natural gas is ignited.
Stop the engine, and keep heat, sparks and flames away.
NOTE: You must be a Lincoln-certified technician to do fuel tank inspection or replacement work.
Removal
NOTE: This procedure degrades the integrity of the fuel tank. If you do it, do not reinstall the original fuel tank. Install a new one.
1. Relieve fuel tank pressure.
2. Remove the left-rear door, rear seat, rear shelf, and trunk floor lid.
3. Raise the vehicle on a lift, and remove the under-floor cover (A) and the under-floor brace (B).
4. Remove the three fuel pipes (A) at the fuel joint block (B) and the two fuel joint block mounting nuts (C).
5. Remove the fuel joint block plate (A) from inside the passenger compartment.
6. Remove the frame members (A), rear panel (B) and disconnect the 6P connector (C).
7. Disconnect the vent hose (A) from the fuel tank (B).
8. Remove the tank frame mounting bolts (A).
9. Push the front seats forward, then cover the seats and floor with a tarp or similar material.
10. With the assistance of two other technicians, lift the frame, and slide the entire fuel tank assembly (A) into the passenger compartment. Be careful not to damage the fuel joint block.
11. Rotate the fuel tank so the fuel joint block and the frame can clear the door opening, then carefully remove the fuel tank assembly from the vehicle.
12. Install the new fuel tank assembly in the reverse order of removal.
13. Open the manual look-down valves on the new tank. (New tank come with these valves closed.)
Disassembly
1. Bolt the fuel tank assembly in the tank fixture A (available from AH special tools department) for disassembly
2. Remove the fuel pipe duct (A) then remove the three fuel pipes (B) from the fuel tank
3. Using the pin type spanner (A), loosen the duct base nut (B), and connector (C)
4. Remove the duct base nut (A) tank valve duct base (B), and the tank base gasket (C)
5. Unbolt the fuel tank bands (A) from the fuel tank frame (B), and remove the old fuel tank (C).
6. With the old fuel tank lifted from the fuel tank frame, remove the fuel tank bands (A) from the fuel tank.
Installation
NOTE: When you relieve the gas pressure from the fuel tank, the fuel tank cannot be reused. Do not reinstall the original fuel tank. Install a new one.
1. Assemble the fuel tank bands (A)
2. Install a new fuel tank (A), fuel tank bands (B) and fuel tank frame (C) on the tank fixture (D).
3. Tighten the bolts (in the sequence shown).
4. Tighten the nuts (in the sequence shown).
5. Tighten the nuts (A) until you get a gap of 11.7 mm (15/32 in.) at the centerline of the bolts.
6. Tighten the nuts and bolts (A).
7. Mark (A) the fuel tank (B) and the fuel tank bands (C).
8. Apply silicone oil or polyaklyleneglycol (PAG) oil to a new O-ring, and carefully install it onto its proper position.
9. Install the fuel joint block and fuel pipes.
10. Install the tank assembly in the reverse order of removal.
11. Do the leak inspection procedures.
12. Apply the CNG warning label and record the CNG tank expiration date.
Fill Procedure
If a tank has less than 690 ± 340 kPa (7.0 ± 3.5 kgf/sq.cm, 100 - 50 psi) of internal pressure and is at an ambient temperature of 32 °F (0 °C) or less, follow the procedure below. Otherwise, fill the tank normally.
1. Fill the fuel tank to 4,800 ± 340 kPa (49.2 ± 3.5 kgf/sq.cm, 700 ± 50 psi) slowly (from a compressor, not from a cascade storage system).
2. Wait one hour.
3. Fill the rest of the tank normally.