E46 Fanatics Forum banner
Status
Not open for further replies.
1 - 16 of 16 Posts

·
Registered
Joined
·
459 Posts
Discussion Starter · #1 ·
Today i was replcing a leaky o ring for a bolt on the valve cover,when i starded to remove the upper bolt it went out all a long with the lower bolt which is attached to the cylinder head,when i go it out i discover that the threads in the head are stripped.what i should i do to fix it? Could a cylinder head machine shop fix it?
Auto part Automotive engine part Vehicle
 

·
Registered
Joined
·
1,030 Posts
Use a Helicoil-style kit to repair it. They have a drill, STI (spiral thread insert) tap, insertion tool, snap-off tool, and a handful of inserts. The head is aluminum so even the cheap kits will work great.

It should take about five minutes, less time than mixing epoxy for a repair that won't hold.

Mark the drill bit for the full hole depth. After drilling re-measure the hole depth and mark the STI tap for 2-3mm shorter. You definitely don't want to bottom out the tap.

Use care when drilling to keep the drilling chips from going into the head, and even more care when cleaning the chips out of the hole. (It's common to do a perfect job containing the chips while drilling, then blow the chips all over when cleaning out the hole.)

Always use a torque wrench or a very gentle touch tightening the nuts. The threaded holes don't strip spontaneously, it's always because someone overtorqued the nut, perhaps thinking that tighter would stop a leak.
 

·
Registered
Joined
·
1,317 Posts
The repair should last the lifetime of your car.

Torque wrenches might take an extra minute or two but payback in spades on avoided sheared/stripped bolts, loose fasteners, ease of disasemble, etc. Recommend as routine habit. Personally I feel safer on the highway and have grown to love hearing that "click, click".
 

·
Registered
Joined
·
1,209 Posts
Yep, i agree for torque wrench importance. I torque all bolts with small 1/4" tool or 1/2" wrench. No stripped bolts.
 

·
Registered
Joined
·
9,171 Posts
the upper bolt it went out all a long with the lower bolt which is attached to the cylinder head,when i go it out i discover that the threads in the head are stripped.
The root cause of this stripped threads is that someone was too lazy to lock the stud to the head. None of those studs should be allowed to come out when removing the valve cover. Keep using the stud as a fastener into the soft aluminum head will soon lead to this problem. If any studs came out, Loctite them to the head.
 

·
Registered
2016 340i xD 6-spd
Joined
·
26,670 Posts
OP...if your valve cover is leaking, it's not because of this 'leaking o-ring.'

That is a grommet and it's just used to ensure the valve cover is held down evenly tight...you do need a new valve cover if you're leaking oil from it.

Also, for this stud, I agree with the comments above about 'maybe' surviving without a time-sert. You could begin by chasing the threads and getting a new stud...and trying loctite. Me? I might even try some teflon plumber's tape, but I sometimes try stupid things. :)
 

·
Registered
Joined
·
1,290 Posts
Mine still ok all these years later, replaced the valve cover back then when I repaired 2 stripped threads with helicoil.
Test threading the inserts without them being inserted is a bit pointless. It works when instructions are followed.
Yep it's m7 for valve cover studs.
 
1 - 16 of 16 Posts
Status
Not open for further replies.
Top