Intake manifold and stripped bolt

[Ron Sebastian]

I have narrowed down a possible oil leak due to a stripped intake manifold bolt. The furthest back towards the fire wall, passenger side. Can I drill a new hole and put a helicoil in? Any tips of the trade would be appreciated.

 

[Ron Sebastian]

Would this work? Helicoil Thread Repair Kit, 3/8"-16 Thread Repair?

 

[Ricko1966]

I have narrowed down a possible oil leak due to a stripped intake manifold bolt. The furthest back towards the fire wall, passenger side. Can I drill a new hole and put a helicoil in? Any tips of the trade would be appreciated.

I'd tap it 10x1.25 and finish with or make a bottom tap if you don't have one. Then run a 10mm bolt as deep as I could. You can probably get away without drilling,or removing the manifold,go slow and easy grease your tap and clean it often

 

[Edelbrock]

Ya, drilling and tapping should work very well.

Or a bunch of Permatex "the right stuff" gasket sealer would work too.

But given the options, I would Helicoil.

Helicoil is a good middle of the road option, allowing for easy application and good reliability.

 

[edgephoto]

I would use a Helicoil. They are a permanent repair. Put a dab of Red Loctite on the insert on the outside so it locks to the head. Then let it dry and fit you intake bolt. Torque to spec.

With Loctite one drop it sufficient. You do not need it dripping. Also if that bolt goes into a coolant passage put a little teflon pipe dope on the bolt threads.

 

[Ron Sebastian]

Thanks for the sanity check guys!

 

[Moodyalaskan]

Also if that bolt goes into a coolant passage put a little teflon pipe dope on the bolt threads.

I would use Permatex #2 Non-hardening instead of Teflon tape. Sealed a lot of machinery with that stuff, never had any leaks and was always able to take it apart later.

 

[Ricko1966]

Helicoil will be significantly bigger pain in the azz,compared to tapping 10mm 1.25 if there is still enough meat. You can probably start a 10mmx1.25 tap without drilling,getting a drill back there is going to be tough. To insert a helicoil,drill size is 25/64s so you will have to remove the manifold and drill the hole 25/64ths then tap it insert the helicoil,reinstall the manifold,bolt everything down. If,you can get a drill back there you can drill the manifold 7/16,drill the head 25/64ths that gives the tap room to get past the manifold,tap the hole,install the insert. OR. 10mm 1.25, .tap the hole,clean the bottom with a bottom tap,put in the longest bolt possible. Done. 1 possible problem will be dependant on how sloppy the holes in the manifold are,you may end up cutting threads in the manifold also. NBD. Screw a nut onto your 10 mm bolt,screw the bolt just into the manifold 3or 4 threads tighten the nut it will pull the threads out,repeat as necessary. Use the longest bolt you can keep using longer and longer until you just have a gap between the head of the bolt and the manifold now use appropriate washers under the head of that bolt. Writing this I just realized depending on the length of the stripped bolt you may get away with just using a longer bolt.

 

[edgephoto]

Teflon pipe dope stays pliable as does #2 Permatex.

@Ricko1966 has maybe a simpler solution but I would not want two different size intake bolts. I like doing things correctly. You decide what you are comfortable with and what is doable.

I like McMaster-Carr for taps and high quality hardware.

 

[Ricko1966]

@edgephoto ^^^^Correctly is kind of subjective there isnt it? Correctly would be replace the head with one that has no damage,2nd closest would be weld the hole shut and remachine. Practical repair is what will work best,for time money and effort. If the manifold were already off,helicoil or time sert would be my first choice. If head and manifold were off and I had another head I'd swap heads.If I could repair by using a different bolt and save myself several hours and a 100.00 I'd use a different bolt.No reason a different bolt wouldn't be permanent.