BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

General Description

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The fuel tank is mounted below the vehicle under the trunk area or rear seat area. The tanks on the E30 and E36 3 Series are divided into 2 sections, bisected by the driveshaft. Fuel is transferred from one side to the fuel pump side by a jet action pump. Fuel being returned by the fuel pressure regulator draws the fuel from the left side of the tank through an orifice, using a venturi effect so no mechanical pump is necessary. The fuel is directed to the right side tank and is picked up by the electrical fuel pump.

REMOVAL & INSTALLATION




CAUTION
Gasoline is extremely flammable and the vapors can be explosive. Work in a well ventilated area away from any sources of ignition. Keep a fire extinguisher of the type for liquid fueled fires within reach during the handling of gasoline. Personal injury or death can result from mishandling gasoline.

E30 3 Series
  1. Turn the ignition switch to the OFF position. Remove the fuel from the tank by draining or siphoning.
  2.  
  3. Remove the rear seat bottom cushion and pull back the plastic sheet.
  4.  
  5. Remove the covers on both sides to expose the fuel pickups and level senders. Mark and disconnect the hoses and electrical plugs.
  6.  
  7. Remove the fuel level senders from both sides of the tank as equipped. Siphon out any remaining fuel from the tank from the openings.
  8.  
  9. Remove the rear muffler, heat shield and the connecting pipe. Remove the driveshaft.
  10.  
  11. Disconnect the fuel pipes and hoses from the tank. Remove the stone guards on both sides.
  12.  
  13. Support the fuel tank. Remove the fastening hardware and tilt the tank down to remove.
  14.  

To install:
  1. Tilt the tank into place and torque the nuts to 18-20 ft. lbs. (25-28 Nm). Torque the bolts to 16-17 ft. lbs. (22-24 Nm).
  2.  
  3. Install the stone guards and connect the hoses and pipes to the tank. Install the driveshaft. Install the connecting pipe and torque to 17-19 ft. lbs. (23-27 Nm).
  4.  
  5. Install the heat shield and torque to 6.0-6.5 ft. lbs. (8-9 Nm). Install the rear muffler.
  6.  
  7. Install the fuel level senders in the tank. Connect the electrical plugs and the hoses.
  8.  
  9. Install the covers and the plastic sheet. Install the rear seat cushion. Torque the drain plug to 16-18 ft. lbs. (21-25 Nm). Fill the tank with gasoline before operating the fuel pumps.
  10.  

E36 3 Series

See Figures 1, 2 and 3



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Fig. Fig. 1: Fuel tank mounting points-E36 3 Series



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Fig. Fig. 2: Disconnect the vent line and unclip from the tank-E36 3 Series



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Fig. Fig. 3: Disconnect the vent pipes 2 and 3-E36 3 Series

  1. Turn the ignition switch to the OFF position. Remove the fuel from the tank by draining or siphoning.
  2.  
  3. Remove the rear seat bottom cushion and pull back the plastic sheet.
  4.  
  5. Remove the covers on both sides to expose the fuel pickups and level senders. Mark and disconnect the hoses and electrical plugs.
  6.  
  7. From under the vehicle, use fuel line block-off clamps on the fuel feed and return lines. This will prevent fuel from running out of the lines once disconnected. Loosen the hose clamps at the connections and disconnect the lines.
  8.  
  9. Remove the 6 screws holding the heat shield. Remove from the vehicle. Remove the driveshaft.
  10.  
  11. Disconnect the parking brake cables from the parking brake lever. Push the cables out from the clamps and pull out of the holder.
  12.  
  13. Disconnect the filler hose from the fuel tank. Support the fuel tank from below. Remove the mounting bolts and lower the tank.
  14.  
  15. Disconnect the tank vent line at the tank. Unclip the lines and remove the fuel tank.
  16.  

To install:
  1. Place the tank into position and connect the vent line. Replace the vent lines into position. Install the tank mounting bolts and torque to 16-17 ft. lbs. (22-24 Nm).
  2.  
  3. Connect the filler hose. Install the parking brake cables by passing through the holders and into the clamps. Connect at the parking brake lever.
  4.  
  5. Install the driveshaft and the heat shield. Connect the fuel feed and return lines. Remove the block-off clamps. Connect the fuel lines and the electrical connectors at the fuel pickups and level senders.
  6.  
  7. Install the rear seat cushion. Fill the tank with gasoline before operating the fuel pumps.
  8.  

E34 5 Series

See Figure 4



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Fig. Fig. 4: Fuel tank components-E34 5 Series

  1. Turn the ignition switch to the OFF position. Remove the fuel from the tank by draining or siphoning.
  2.  
  3. Remove the trunk trim panels to expose the cover at the right, front of the trunk.
  4.  
  5. Remove the cover to expose the fuel pickup and level sender. Mark and disconnect the hoses and electrical plugs.
  6.  
  7. Open the fuel filler door and remove the rubber bellows. Remove the right, rear wheel and remove the wheelwell trim to expose the expansion tank. Disconnect the vent hoses.
  8.  
  9. Support the tank. Remove the heat shield. Remove the strap bolts and remove the tank.
  10.  

To install:
  1. Install the fuel tank, replacing the strap liners and tank pads as necessary. Torque the strap bolts to 6.0-6.5 ft. lbs. (8-9 Nm).
  2.  
  3. Install the heat shield. Connect the vent lines and install the wheel well trim. Install the fuel filler opening rubber bellows.
  4.  
  5. Connect the fuel hoses and electrical plugs. Install the cover in the trunk and the trunk trim panels.
  6.  
  7. Fill the tank with gasoline before operating the fuel pumps.
  8.  

Fuel Level Sender

E30 3 Series
  1. If the tank is full, remove some fuel to lower the level.
  2.  
  3. Remove the rear seat cushion and peel back the insulating sheet to access both covers.
  4.  
  5. Remove the screws from the covers and lift off. Pull of the electrical plug and disconnect the fuel lines. Catch any spilled fuel.
  6.  
  7. If equipped with a level sender held by 4 screws, remove the 4 screws from the sender portion of pickup assembly on the right side. Slowly remove the sender to allow the fuel to drain into the tank. If there are no screws, rotate the assembly counterclockwise and remove.
  8.  
  9. Rotate the left side sender assembly counterclockwise and pull out slowly. Allow the fuel to drain back into the tank.
  10.  

To install:
  1. Replace the gasket and lower the left side sender assembly into the fuel tank. Rotate the assembly clockwise to lock into place.
  2.  
  3. Replace the gasket and lower the fuel level sender into the pickup assembly, if equipped. Replace the screws.
  4.  
  5. Connect the fuel lines and electrical connector. Replace the covers and the insulating sheet. Install the rear seat cushion.
  6.  

E36 3 Series
RIGHT SIDE

See Figure 5



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Fig. Fig. 5: Right side fuel level sender components-E36 3 Series

  1. Drain the fuel from the fuel tank if the level is high. It is best to do this procedure with little fuel in the tank.
  2.  
  3. Remove the rear seat cushion and pull off the cover on the right side to expose the top of the fuel pickup assembly.
  4.  
  5. Disconnect the plugs on the top of the assembly. The black connector is for the fuel pump. The white connector is for the fuel level sender.
  6.  
  7. Mark and disconnect the fuel lines. Using tool 16 1 020 or equivalent, rotate the mounting ring and remove the assembly. Press the level arm in slightly to make clearance when removing.
  8.  

To install:
  1. The entire unit must be replaced. The individual parts are not serviceable.
  2.  
  3. Using a new seal and mounting ring, install the assembly. Move the unit from side to side to make sure the level sender is free and in the correct location. There is a rib on the flange that should align with a mark on the fuel tank.
  4.  
  5. Using tool 16 1 020 or equivalent, torque the mounting ring to 27-31 ft. lbs. (37-43 Nm).
  6.  
  7. Connect the fuel lines and the electrical connectors. Install the cover and rear seat.
  8.  

LEFT SIDE

See Figure 6



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Fig. Fig. 6: Left side fuel level sender components-E36 3 Series

  1. Drain the fuel from the fuel tank if the level is high. It is best to do this procedure with little fuel in the tank.
  2.  
  3. Remove the rear seat cushion and pull off the cover on the left side to expose the top of the fuel pickup assembly.
  4.  
  5. Disconnect the plugs on the top of the assembly.
  6.  
  7. Mark and disconnect the fuel lines. Using tool 16 1 020 or equivalent, rotate the mounting ring and remove the assembly. Press the level arm in slightly to make clearance when removing.
  8.  

To install:
  1. The entire unit must be replaced. The individual parts are not serviceable.
  2.  
  3. Using a new seal and mounting ring, install the assembly. Insert the fuel pickup and float into the tank. Press the center rod upwards and in the direction of the pickup. Release the rod so it sits in the depression on the bottom of the tank. There is a rib on the flange that should align with a mark on the fuel tank.
  4.  
  5. Using tool 16 1 020 or equivalent, torque the mounting ring to 27-31 ft. lbs. (37-43 Nm).
  6.  
  7. Connect the fuel lines and the electrical connector. Install the cover and rear seat.
  8.  

E34 5 Series
  1. Drain the fuel from the fuel tank if the level is high. It is best to do this procedure with little fuel in the tank.
  2.  
  3. Remove the trunk panels to expose the tank access cover on the right side, front corner. Remove the screws holding the cover.
  4.  
  5. Mark the fuel lines and disconnect them. Disconnect the electrical connection.
  6.  
  7. The models with M20, M30 and M50 engines are equipped with a large mounting ring that holds the fuel pump and level sender assembly. The mounting ring is removed using tool 16 1 020 or equivalent. The tool grips the edge of the mounting ring and allows the use of a breaker bar or socket wrench to remove the ring.
  8.  
  9. The M5 with the S38 engine has the fuel pump and level sender assembly retained with 8 screws or nuts around the perimeter. Remove the screws to remove the assembly.
  10.  
  11. Remove the assembly from the tank slowly to avoid spilling any fuel. The level sender with come out first. Compress the mounting hooks and remove the fuel pump.
  12.  

To install:
  1. Install the fuel pump into the tank and make sure the mounting hooks are secure on the fuel pump.
  2.  
  3. Replace the gasket and install the fuel level sender. Tighten the nuts or screws on the M5. On the mounting ring type units, using tool 16 1 020 or equivalent, torque the mounting ring to 27-31 ft. lbs. (37-43 Nm).
  4.  
  5. Connect the wires and the fuel lines. Replace the cover and the trunk trim.
  6.  

 
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