Stripped threads on aluminum valve cover

[V1]

Today I replaced the spark plugs in my Mazda 6. It didn't take much for me to strip one of the 1/4" bolts that hold the plug coils to the valve cover.

Re-tapping a bigger bolt is not an option - it won't fit through the coil housing. I've read about Helicoil and Permatex which both seem viable. Should I focus on using one of those, or do I have other options?

 

[labman]

Maybe a heli coil. I have had good luck with Permatex, but it may not take the heat there.

Maybe have a welding shop weld the hole shut, then drill and tap. Otherwise, the bone yard.

 

[tom slick]

heli-coil or take it to someone who can heli-coil it for you.

 

[Clyde65]

Helicoil is the best way to go in this situation. But you have to know how to use a drill, turn a tap and install the insert correctly.

 

[V1]

I just used some teflon tape on the bolt. It worked like a charm.

 

[Schmoe]

Depending on how much torque you'll need to secure the plug coils, I'd go with what V1 said. I've fixed many threads that way.

 

[alreadygone]

Agree with another Todd. None of the names for teflon tape repair will pass the nanny-net here.

Use heli-coil or king-sert.

Bob

 

[XS650]

quote:

---

Originally posted by alreadygone:
Agree with another Todd. None of the names for teflon tape repair will pass the nanny-net here.

Use heli-coil or king-sert.

Bob

---

Keene-sert?

 

[V1]

Teflon tape is more or less permanently used for gas pipes in a home fireplace. So why not in a gasoline engine?

 

[labman]

Teflon tape is fine in a gas engine as a thread lubricant and seal. Just jamming something in to take up the gap? I would go with wire screen or something.

 

[another Todd]

Pipe threads are "self locking" and properly sized male and female threads, and the tape only seals the threads. In your case the male and female threads are not properly sized, the female threads are stripped and probably somewhat missing. So putting tape on the male threads and pushing it in (or screwing it in but if the threads are gone it isn't biting anything)is the equivalent of using a nail. IMO won't last.

 

[V1]

Ok, so you're just saying that it won't hold FOREVER. I can accept that. Can you forsee any other issues? Right now, I feel that it's a pretty darn good fix.

I'll be sure to check it periodically to make sure it's holding up too. If it gets loose, I'll just refresh it with some new tape. Like I said, a semi-permanent remedy. Nothing wrong with that right?

 

[alreadygone]

XS650,

Yes!

V1,

Aw,,never mind.

Bob

 

[another Todd]

V1, yes it won't hold forever. Issues---perhaps, the coil may need tight clean threads for a ground. Teflon I believe would tend to insulate the bolt.

As far as----"Like I said, a semi-permanent remedy. Nothing wrong with that right?

If thats the way you feel, go for it. Me, I'd take the 10 minutes to fix it right and never have to check it again.

 

[labman]

If you go heli coil, check to see if the bolt is really 6 mm or somthing, not 1/4''.

 

[another Todd]

Heli-coil or equiv., or the permatex type thread repair products will both work. Teflon tape on the threads should not be considered a quality repair or permanent.

 

[Clyde65]

V1, if you ever get the mechanical motivation to install a Helicoil on something, let me know. I can tell you which kit you need, where to buy it and how to install it.

Clyde -

 

[mechtech]

Is that bolt used as a ground?
I wouldn't like that Teflon there, for a variety of reasons.
Can you enlarge the coil hole slightly, and then use a bigger bolt?
How about going longer/deeper with a stock sized one, and possibly using sealer?

 

[TallPaul]

I have a stripped hole for one tranny pan bolt. Very slow leak. I was thinking of trying the teflon tape. If that does not work, a piece of screen.

quote:

---

Originally posted by alreadygone:
None of the names for teflon tape repair will pass the nanny-net here.

---

??? Do you mean no brand of teflon tape has yet been successfully used for this type of repair?

 

[V1]

Does the bolt ground the coil? Good question - I don't know! There is still SOME metal-to-metal contact between the bolt and the valve cover.

I guess I have to run the car to find out. It's been sitting in the garage since I put the tape on the bolt...