The one technical item no video even mentions is timing. Does timing need to be set? I did a tensioner on a Benz 2005 C240 2.6L Timing had to be set at 40 degrees before TDC. At the timing mark, the chain is loose. The tensioner comes out and goes in easily. If timing is not set, screwing in a tensioner can strip threads, break guides, or even break the chain.

From videos seen, the M54 does not require a timing mark set to install a new tensioner.

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'06 X5 3.0i - bought @143,123 miles (12/26/20)