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

ENTIRE SYSTEM

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The exhaust system is removed in one piece. The components of the exhaust system can be disconnected once the entire system has been removed. Allow the exhaust system to cool down completely before working on it.

REMOVAL & INSTALLATION E30 3 Series



WITH M20 ENGINE
  1. Disconnect the oxygen sensor and move the wire out of the way.
  2.  
  3. Remove the exhaust manifold connection nuts.
  4.  
  5. Remove the exhaust pipe transmission mount.
  6.  
  7. Remove the mount on the rear axle subframe.
  8.  
  9. Disconnect the rear muffler mounts and remove the exhaust system.
  10.  

To install:
  1. Install the exhaust system to the car. Use new rubber mounts. Insert the rear muffler into its mounts and slide the mounts forward to preload the rubber ring 0.236 inch (6mm). Tighten the mounts. There should be a maximum torque of 10 ft. lbs. (14 Nm).
  2.  
  3. Loosely attach the transmission mounting point, but do not tighten.
  4.  
  5. Connect the rear axle subframe mount and the manifold nuts. Locate the tail pipes evenly in the opening.
  6.  
  7. Tighten the rear axle subframe mount to 16 ft. lbs. (22 Nm) and the manifold nuts to 36 ft. lbs. (50 Nm). Use new nuts and gaskets. Coat the studs with antisieze.
  8.  
  9. Tighten the transmission mount to 16 ft. lbs. (22 Nm). Check that the exhaust system does not strike any points under the car. Connect the oxygen sensor. Check for exhaust leaks.
  10.  

WITH M42 ENGINE
  1. Disconnect the oxygen sensor and move the wire out of the way.
  2.  
  3. Remove the exhaust manifold connection nuts.
  4.  
  5. Remove the exhaust pipe transmission mount.
  6.  
  7. Remove the mount on the rear axle subframe.
  8.  
  9. Disconnect the rear muffler mounts and remove the exhaust system.
  10.  

To install:
  1. If the catalytic converter was removed, install the catalytic converter and connect the flanges. Tighten the bolts to 8-10 ft. lbs. (11-14 Nm) so the springs are flattened. Loosen the nuts 1 1 / 2 turns.
  2.  
  3. Install the exhaust system to the car. Use new rubber mounts. Insert the rear muffler into its mounts and slide the mounts forward to preload the rubber ring 0.236 inch (6mm). Tighten the mounts. There should be a maximum torque of 10 ft. lbs. (14 Nm).
  4.  
  5. Loosely attach the transmission mounting point, but do not tighten.
  6.  
  7. Connect the rear axle subframe mount and the manifold nuts. Locate the tail pipes evenly in the opening.
  8.  
  9. Tighten the rear axle subframe mount to 16 ft. lbs. (22 Nm) and the manifold nuts to 36 ft. lbs. (50 Nm). Use new nuts and gaskets. Coat the studs with antisieze.
  10.  
  11. Tighten the transmission mount to 16 ft. lbs. (22 Nm). Check that the exhaust system does not strike any points under the car. Connect the oxygen sensor. Check for exhaust leaks.
  12.  

WITH M42 ENGINE
  1. Disconnect the oxygen sensor and move the wire out of the way.
  2.  
  3. Remove the exhaust manifold connection nuts.
  4.  
  5. Remove the exhaust pipe transmission mount.
  6.  
  7. Remove the mount on the rear axle subframe.
  8.  
  9. Disconnect the rear muffler mounts and remove the exhaust system.
  10.  

To install:
  1. If the catalytic converter was removed, install the catalytic converter and connect the flanges. Tighten the bolts to 8-10 ft. lbs. (11-14 Nm) so the springs are flattened. Loosen the nuts 1 1 / 2 turns.
  2.  
  3. Install the exhaust system to the car. Use new rubber mounts. Insert the rear muffler into its mounts and slide the mounts forward to preload the rubber ring 0.236 inch (6mm). Tighten the mounts. There should be a maximum torque of 10 ft. lbs. (14 Nm).
  4.  
  5. Loosely attach the transmission mounting point, but do not tighten.
  6.  
  7. Connect the rear axle subframe mount and the manifold nuts. Locate the tail pipes evenly in the opening.
  8.  
  9. Tighten the rear axle subframe mount to 16 ft. lbs. (22 Nm) and the manifold nuts to 36 ft. lbs. (50 Nm). Use new nuts and gaskets. Coat the studs with antisieze.
  10.  
  11. Tighten the transmission mount to 16 ft. lbs. (22 Nm). Check that the exhaust system does not strike any points under the car. Connect the oxygen sensor. Check for exhaust leaks.
  12.  

WITH S14 ENGINE
  1. Remove the exhaust manifold connection nuts.
  2.  
  3. Remove the rear axle subframe mounts and the rear muffler mount.
  4.  
  5. Lower the exhaust system.
  6.  

To install:
  1. Install the exhaust system under the car. Attach the rear and subframe mounts using new rubber mounts.
  2.  
  3. Replace the manifold connection gasket, coat the studs with antisieze and mount the exhaust pipe to the manifold. Torque the nuts to 36 ft. lbs. (50 Nm).
  4.  
  5. Adjust the mounts to position the exhaust pipe in the opening at the rear of the car. Tighten the mounts to 16 ft. lbs. (22 Nm).
  6.  
  7. Check that the exhaust system does not strike any points under the car. Check for exhaust leaks.
  8.  

E36 3 Series

WITH M42 ENGINE
  1. Disconnect the oxygen sensor and remove the exhaust manifold connection nuts.
  2.  
  3. Remove the clamp around the exhaust pipe from the transmission bracket. Do not remove the bracket from the transmission.
  4.  
  5. Remove the rubber rings from the rear axle subframe and disconnect the muffler from the rear clamps. Remove the exhaust system.
  6.  

To install:
  1. Install the muffler into the clamps. Preload the mounts by sliding the clamps forward 0.59 inch (15mm) and tightening to 10 ft. lbs. (14 Nm).
  2.  
  3. Connect the rubber rings and the manifold connection. Replace the manifold connection gasket, coat the studs with antisieze and mount the exhaust pipe to the manifold. Torque the nuts to 36 ft. lbs. (50 Nm).
  4.  
  5. Connect the transmission mounting point and tighten to 16 ft. lbs. (22 Nm).
  6.  
  7. Connect the oxygen sensor. Check the positioning of the system and adjust the mounts as necessary. Check for exhaust leaks.
  8.  

WITH M50 ENGINE
  1. Disconnect the oxygen sensor and remove the exhaust manifold connection nuts. Remove the transmission to engine joint crossmember on automatic transmission equipped cars. The engine and transmission will still be supported by the forward and rear mounts.
  2.  
  3. Remove the clamp around the exhaust pipe from the transmission bracket. Do not remove the bracket from the transmission.
  4.  
  5. Remove the rubber rings from the center mounting point and disconnect the muffler from the rear clamps. Remove the exhaust system.
  6.  

To install:
  1. Install the muffler into the clamps. Preload the mounts by sliding the clamps forward 0.59 inch (15mm) and tightening to 10 ft. lbs. (14 Nm).
  2.  
  3. Connect the rubber rings and the manifold connection. Replace the manifold connection gasket, coat the studs with antisieze and mount the exhaust pipe to the manifold. Torque the nuts to 22 ft. lbs. (30 Nm), then 36 ft. lbs. (50 Nm).
  4.  
  5. Connect the transmission mounting point and tighten to 16 ft. lbs. (22 Nm). Install the crossmember.
  6.  
  7. Connect the oxygen sensor. Check the positioning of the system and adjust the mounts as necessary. Check for exhaust leaks.
  8.  

E34 5 Series See Figures 1, 2 and 3

Click image to see an enlarged view

Fig. Fig. 1: Pull the shield off the oxygen sensor



Click image to see an enlarged view

Fig. Fig. 2: Exhaust manifold connection nuts on M50 engine



Click image to see an enlarged view

Fig. Fig. 3: Transmission mount for exhaust system. This should be the last item to be tightened when the exhaust system is installed

EXCEPT WITH S38 ENGINE
  1. Disconnect the oxygen sensor and move the wire out of the way.
  2.  
  3. Remove the exhaust manifold connection nuts.
  4.  
  5. Remove the exhaust pipe transmission mount.
  6.  
  7. Remove the mount on the rear axle subframe.
  8.  
  9. Disconnect the rear muffler mounts and remove the exhaust system.
  10.  

To install:
  1. Install the exhaust system to the car. Use new rubber mounts. Insert the rear muffler into its mounts and slide the mounts forward to preload the rubber ring 0.275 inch (7mm). Tighten the mounts. There should be a maximum torque of 10 ft. lbs. (14 Nm).
  2.  
  3. Loosely attach the transmission mounting point, but do not tighten.
  4.  
  5. Connect the rear axle subframe mount and the manifold nuts. Locate the tail pipes evenly in the opening.
  6.  
  7. Tighten the rear axle subframe mount to 16 ft. lbs. (22 Nm) and the manifold nuts to 36 ft. lbs. (50 Nm). Use new nuts and gaskets. Coat the studs with antisieze.
  8.  
  9. Tighten the transmission mount to 16 ft. lbs. (22 Nm). Check that the exhaust system does not strike any points under the car. Connect the oxygen sensor. Check for exhaust leaks.
  10.  

WITH S38 ENGINE
  1. Disconnect the oxygen sensor and move the wire out of the way. Remove the heat shield.
  2.  
  3. Remove the exhaust manifold connection nuts.
  4.  
  5. Remove the exhaust pipe transmission mount.
  6.  
  7. Remove the mount on the rear axle subframe.
  8.  
  9. Disconnect the rear muffler mounts and remove the exhaust system.
  10.  

To install:
  1. Install the exhaust system to the car. Use new rubber mounts. Insert the rear muffler into its mounts and slide the mounts forward to preload the rubber ring 0.197 inch (5mm). Tighten the mounts. There should be a maximum torque of 16 ft. lbs. (22 Nm).
  2.  
  3. Loosely attach the transmission mounting point, but do not tighten.
  4.  
  5. Connect the rear axle subframe mount and the manifold nuts. Locate the tail pipes evenly in the opening.
  6.  
  7. Tighten the rear axle subframe mount to 16 ft. lbs. (22 Nm) and the manifold nuts to 30 ft. lbs. (42 Nm). Use new nuts and gaskets. Coat the studs with antisieze.
  8.  
  9. Tighten the transmission mount to 16 ft. lbs. (22 Nm). Check that the exhaust system does not strike any points under the car. Connect the oxygen sensor. Check for exhaust leaks.
  10.  

 
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