07, R56, N12 non turbo engine. I just had a knock sensor code. Does this require heat to remove the bolt. Not too bad to access from below. I think I can get everything out of the way to do so.
Regards,
Briscoe

 

I mean, it shouldn't require heat by design. If a bolt is rusted or stuck heat can help, but I wouldn't expect to need heat with that particular bolt.

If I can trust my Bentley manual it's just a remove & replace job. The tightening torque spec is 20 NM (14.7 ft. lb) and it says "replace o-ring"

 

Thank you, I would not imagine needing heat if there is an O ring. The replacement part vendor recommended using red lock tight when reinstalling. I'm still waiting on the part so I would not have seen if it comes with one.

 

Well, even the pelican parts article mentions red loctite. In that case, heat may be needed to break the stickiness of the red loctire.

Red seems overly aggressive though. If you reuse the bolt, I would suggest to apply sparingly.

Also torquing to spec seems very important here.
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You're right: if I check the parts diagram, the OEM bolt uses encapsulated red loctite. Seems like overkill but what do I know.

There's also no "o-ring" I can find in the diagram, so it looks like Bentley was wrong there. Maybe they meant to replace the loctite.

 

Completed the work, replacing the sensor from below the car. It had some type of lock-ite on the threads. I used the blue type to go back with. Thanks for the reminder to torque to spec, which is 14.7 ft lbs. Why haven't they invented sockets that are magnetic yet. What a pain trying to snake the bolt around stuff without it falling off the extension and socket 50 times. Grease was not heavy enough to hold it on the socket either.

 

Not helpful anymore, but I usually just wrap a bit of electrical tape or painters tape around the socket and form like a 1mm lip that holds the bolt. Then after it's seated in the threads, just pull out the extension, remove tape, and torque to spec.

 

I'll give it a shot, although hopefully it'll be a long time before I do something that tricky.