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#1 Oil sump plug thread

Posted: Mon Oct 18, 2021 1:14 pm
by Direwolf
I have a series 3, 1971-V12.

I have a Helicoil insert that is sticking out of my oil sump plug hole, l have seen different posts with different suggestions but not a clear description for a solution. If I try to put another helicoil in - should l retap the original thread after removing the insert ( would that be 5/18x18unf. M18x2 ) or drill a bigger ‘clean bore’ and tap/helicoil that? Or…

I read about Time Sert’s, what size should I use? This solution sounds interesting as this may prevent the same problem happening again.

Would you recommend removing the sump to do this?

Many thanks for your help

Bob

#2 Re: Oil sump plug thread

Posted: Mon Oct 18, 2021 11:51 pm
by abowie
I would pull the old helicoil out and replace it with one of the same size. Grab it with a pair of pliers and it should come out like a spring.

If that fails then you could drill it oversize.

Do NOT try to put a tap down to straighten out your current helicoil. It will jam in place and be very difficult to remove.

#3 Re: Oil sump plug thread

Posted: Tue Oct 19, 2021 7:45 pm
by Direwolf
Thank you Andrew for your reply, l am in Uk for a couple of days and will get the helicoil thread repair kit while here and will try to do as you suggest when l get back to France. I wondered about the Time Sert solution as it may be more durable. I guess the helicoil should be fine l will just make sure l do the oil changes from now on and make sure it is not over tightened. Thank you. Bob

#4 Re: Oil sump plug thread

Posted: Wed Oct 20, 2021 5:21 am
by Allrand
I use an Autovac to suck the oil out, no mess, no risk of stripping threads, no need to replace copper gasket or jack car up & crawl under!