How to Remove an M42 BMW Cylinder Head

1. Place the car in neutral and setting the handbrake to keep it from moving. Detach the battery cables and keep them pushed away from the battery (if necessary, use tape to keep them down).
2. Move the two plastic clips at the top of radiator to remove the fan shroud. Loosen the clips by pushing the pins at the center. Loosen the screw at the bottom of the radiator to drain the fluid. Place a bucket or pan underneath the screw for the fluid to drain into. Drain only the radiator fluid, not the oil. Unplug the radiator hose.
3. Remove the spark plug wires and the wire loom. Make sure to keep track or which wire goes to which plug as the using the wrong plug will lessen the engine's performance. If necessary use a felt marker or other writing utensil to mark the wires and plugs. Loosen the two nuts on the exhaust side of the wire loom to remove it.
4. Unscrew the coil packs nuts. These are in the bracket on the wheel well. Push the wiring to the coil packs away. No need to remove them, just make sure that all wires are pushed away, along with the spark plug wires. Remove each of the spark plugs, followed by the valve cover and the mass airflow sensor boot. It isn't necessary to remove the mass airflow sensor or the air filter.
5. Remove the hoses and electrical clips from along the intake's top. Keep an eye on the small, rubber gaskets inside the electrical clips as they may fall out. Again it may be best to mark or label each hose and connection for when they need to be reinstalled.
6. Remove the bolt attaching the throttle body and remove the the throttle body. There is no need to disconnect the cable but be cautious while placing it aside. Remove the upper intake manifold and place it aside. Be sure to mark or remember each of the connections. Remove the nuts from the top of the wiring harness and disconnect every clip possible. Connections will depend on the model year of the engine but detach as many as possible.
7. Remove the fuel rail bolts, fuel injector clips and the injector electrical connector wire clips. Use the pliers to carefully bring these off and do not lose them. Once all four are detached remove the electrical box. Remove the fuel injectors. Remove the lower intake manifold nuts and pull the manifold away.
8. Remove the water hose. Remove the exhaust manifold nuts, be careful as the studs will often come with them. Remove the cam sensor. Use the Allen wrench to detach it from the front of the timing case.
9. Remove the thermostat housing and the thermostat. Remove the front timing case cover. Remove the chain tensioner. This is located at the right side of the engine block.
10. Remove the two bolts holding on the plastic chain guide. Use the Allen wrench for these. Remove the bolts from each cam gear and slide the gears away. Once again, make a note on their position so they don't get confused.
11. Loosen each of the nuts holding in the cam retainers. Do this in a star pattern. Remove the cams and cam towers.
12. Remove the ten head bolts. This requires a TORX socket and a breaker bar. Loosen the head bolts in a star pattern, just a couple of turns will bring them out.
13. Remove the cylinder head from the engine being very careful to not hurt yourself as it will may require a good deal of effort to remove the head. Be aware that coolant, oil and other fluids will spill out out once the head is removed.