DIY: 550i Timing Cover Replacement
 

I am doing this write up because I could not find one when I needed one. Changing the driver side (American) timing cover on a 550 has been an absolute nightmare due to the oil cooler line obstructing access to the bottom bolt. After 3 days and almost giving up I figured it out.

The idea is to remove a metal clamp which holds the two oil cooler lines together. The clamp is located just below the line closest to the front of the engine. It is held in by a torx (T25 I believe) screw which faces down leaving little to no access.
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First, release the bolts holding the power steering fluid line. That is the metal line which goes across the front of the engine. There is one bolt on the vacuum pump and another on the driver side timing cover. This line is also held by the metal clamp which you are trying to release. Once the steering line is released push it down as much as you can so you can get a tiny ratchet as I have or probably a L shaped torx driver similar to the L shaped Allen key. The ratchet I have was a very tiny one which I purchased from Advance Auto, I have also seen it at AutoZone. It will be tedious but it can be done.
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Once you have released the screw pull the oil cooler line out of the way. It didn't feel like it wanted to move but it will move, be very careful if this line breaks you are f!cked, prepare to spend big. I did not replace the screw I was trying to but that is equally as difficult. I resorted to zip tieing the clamp.
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