Sheared bolt (oil filter housing) - how can I get it out?

[RhythmMachine]

On my N55 I was doing my belt/pulleys/tensioner and replacing my oil cooler gasket and oil filter housing gasket and ran into a couple of problems with the oil filter housing gasket.



First, the bolt that's underneath (that everyone complains about) would not turn, despite oiling it, waiting, and heating it (and I was using the correct e-12 socket). When I saw that the head was starting to get a twist in it I decided not to push my luck and skip the oil filter housing gasket for now.



I set my torque wrench to the spec 16nm and tightened up the bolt under the intake manifold, and then started on the final bolt on the top. Unfortunately, it snapped partway down, so the bottom part of the bolt is threaded into the engine block. The break is about 1cm below the surface of the hole.



This is the location of the bolt that broke:




So, will a left-thread screw/bolt extractor kit like this be my best bet? Something like this?





I assume that I would need a good bit to drill into the bolt, then use one of the extractor bits to bite in and reverse it out. I don't have an impact wrench, so it would be a combination of regular power drill or hand tools.



Any other suggestions?

[andrewwynn]

I have good luck with left handed drill bits. Start small work your way up. When you get to about 80% of the bolt diameter the bit catches on the way out and you will have a threaded cylinder on the drill bit. I prefer this method as it pushes from the bottom v pulls from the top.

Is the bolt one that holds down the filter housing or the intake manifold?

https://www.realoem.com/bmw/enUS/sho...diagId=11_4466

6,7,8 are the ofh bolts

https://www.realoem.com/bmw/enUS/sho...diagId=11_4470

6 is the one bolt for the intake the rest are all nuts on studs.

If it wasn't the corner one I'd say leave it. When i did my OFHG i discovered a previous mechanic left off one off the nuts and i never had a code and did not see a sign of venting intake air.

[RhythmMachine]

Originally Posted by andrewwynn

I have good luck with left handed drill bits. Start small work your way up. When you get to about 80% of the bolt diameter the bit catches on the way out and you will have a threaded cylinder on the drill bit. I prefer this method as it pushes from the bottom v pulls from the top.

Is the bolt one that holds down the filter housing or the intake manifold?

https://www.realoem.com/bmw/enUS/sho...diagId=11_4466

6,7,8 are the ofh bolts

https://www.realoem.com/bmw/enUS/sho...diagId=11_4470

6 is the one bolt for the intake the rest are all nuts on studs.

If it wasn't the corner one I'd say leave it. When i did my OFHG i discovered a previous mechanic left off one off the nuts and i never had a code and did not see a sign of venting intake air.

It is, unfortunately, #8, which is likely necessary. #6 is the one that I wasn't able to undo, but I think that the broken one is far enough down that if I remove #7 again I may be able to rotate the oil filter housing on the remaining bolt (#6) to have easy access to try to remove the stud from #8.



If that works, and I pick up three new replacement bolts from BMW, the question is whether I should try to cut or somehow otherwise remove #8, both so that I can finish the gasket replacement job and also so that I can have 3 solid connection points going forward. I'd have to end up leaking oil from there right after replacing my belt/tensioner/pulleys.

[andrewwynn]

6 you should be able to drill out from the top with right hand drill bit or twist off the head first and drill out on the bench. It of course will be easier to repair with the housing removed.

A recent thread with same job involved the 7 or 8 getting striped in the head, repair was using a longer bolt as the threading goes father in the head than the stock bolt.

If you drill out 80% of the 6 bolt it should weaken it to turn it out from the head.

[Daytonawim]

Drill a whole, and use a left tread bolt to get it out. (Like said) it could not be that tight.

But the great question is a bolt of that size that breaks at 16 Nm is very odd.
16 Nm is near hand tight. Check you torque wrench I would say!