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

Timing Belt Front Cover

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REMOVAL & INSTALLATION M20 Engine



The M20 engine is equipped with a timing belt, as opposed to a timing chain as is usual bmw style. The distributor guard plate is actually the upper timing belt cover.

  1. Disconnect the negative battery cable. Remove the distributor cap and rotor. Remove the inner distributor cover and seal.
  2.  
  3. Remove the 2 distributor guard plate attaching bolts and one nut. Remove the rubber guard and take out the guard plate (upper timing belt cover).
  4.  
  5. Rotate the crankshaft to set No. 1 piston at tdc of its compression stroke.
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At tdc of No. 1 piston compression stroke, the camshaft sprocket arrow should align directly with the mark on the cylinder head.

  1. Remove the radiator.
  2.  
  3. Remove the lower splash guard and take off the alternator, power steering and air conditioning belts.
  4.  
  5. Remove the crankshaft pulley and vibration damper.
  6.  
  7. If equipped with a 2 piece hub, hold the crankshaft hub from rotating with the proper tool. Remove the crankshaft hub bolt.
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  9. Install the hub bolt into the crankshaft about 3 turns and use the proper gear puller, to remove the crankshaft hub.
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  11. Remove the bolt from the engine end of the alternator bracket. Loosen the alternator adjusting bolt and swing the bracket out of the way.
  12.  
  13. Lift out the tdc transmitter and set it aside.
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  15. Remove the remaining bolt and lift off the lower timing belt protective cover.
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  17. Loosen the timing belt tensioner roller bolts and push the roller in to remove the belt. Remove the intermediate shaft sprocket bolt and the sprocket.
  18.  
  19. Loosen the oil pan bolts and remove the 3 front pan bolts that go into the timing cover. Use a thin blade to loosen the oil pan gasket from the cover. Remove the 6 bolts holding the cover and remove from the engine.
  20.  

To install:
  1. Remove the oil pan and replace the gasket using non-hardening sealer at the joints. Replace the seals in the cover if necessary. Install the timing cover with new gaskets and tighten the M6 bolts to 6-7 ft. lbs. (8-10 Nm) and the M8 bolts to 15-17 ft. lbs. (20-24 Nm). Tighten the oil pan M6 bolts to 6.5-8.0 ft. lbs. (9-11 Nm) and the M8 bolts to 13-15 ft. lbs. (18-22 Nm).
  2.  
  3. Install the intermediate shaft sprocket and timing belt. Tighten the belt.
  4.  
  5. Install the lower timing protective cover and tighten the bolt. Install the tdc sender.
  6.  
  7. Replace the alternator bracket. Install the crankshaft hub and torque the nut to 281-309 ft. lbs. (390-430 Nm).
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  9. Install the vibration damper and pulley. Torque the bolts to 17 ft. lbs. (23 Nm).
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  11. Install the upper cover and nut. Install the rubber guard. Check the condition of the O-ring and install the upper cover. Install the rotor and distributor cap.
  12.  
  13. Install the accessories and belts. Install the splash shield and fill the cooling system with coolant mixture. Bleed the cooling system.
  14.  

OIL SEAL REPLACEMENT



  1. Disconnect the negative battery cable. Remove the front engine cover.
  2.  
  3. Press the 2 radial oil seals out of the front engine cover.
  4.  
  5. Install the oil seals flush with the front engine cover using the proper tools.
  6.  
  7. Install the front engine cover. Connect the negative battery cable.
  8.  

 
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