DIY: E39 M5 Cam Chain Tensioner

The cam chain tensioners on E39 M5’s are a known weak point and at around the 70,000-mile mark they are likely to start making that tell tale rattle on start up. Follow our easy 4 step guide and fix yours yourself.

1) Remove the driver’s side air box. It’s held in by a 10mm bolt, and 2 jubilee clips.

2) On the L/H bank of the V8 is a 19mm bolt, down by the air-conditioning pipes. That holds the tensioner in, undo that and it will slide out. There will be a little bit of oil so have some paper towel to hand.

3) Put the new tensioner (P/N B11.31.1.406.261) in the hole. Mine was £97 from BMW, and don’t forget the metal washer either(B07.11.9.963.355). Getting it in and the threads to engage takes patience, so persevere and you’ll get there.

4) Tighten it down to 50nm and put the air box back in. That’s it job done.

So before you start panicking about expensive VANOS diagnosis, do the easy, cheap jobs first, you might surprise yourself. Just listen to the difference.

AuthorGraeme Franklin
Photography: Graeme Franklin

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