Lower intake manifold bolt threaded - how bad?

[usapadyra]

Hey,

I was replacing the lower and upper intake manifold gaskets on my 98 4.0 SOHC. 50000 miles with the check engine light but I finally decided to tackle it.

Sadly, when double checking the final torque on the lower intake bolts (I'm doing 150 inch pounds) I ended up threading one of them. It started spinning and offers very little resistance now. Took it out - the bolt looks OK so I think I must have stripped the bore itself.

I've red circled the one that it is in the attached picture.

If all the other bolts are snug to spec, how bad is this? Will it start leaking straight away or should it be ok with the pressure from the surrounding bolts?

I cleaned the heads and everything else very well so the gaskets should have a solid mating surface.

Is there some kind of product I can put on the bolt that could help??

ARG!

 

[Josh P]

I'd tap new threads, something slightly larger.

 

[C420sailor]

Or do a helicoil/timesert

 

[Lee's Automotive]

Hey,

I was replacing the lower and upper intake manifold gaskets on my 98 4.0 SOHC. 50000 miles with the check engine light but I finally decided to tackle it.

Sadly, when double checking the final torque on the lower intake bolts (I'm doing 150 inch pounds) I ended up threading one of them. It started spinning and offers very little resistance now. Took it out - the bolt looks OK so I think I must have stripped the bore itself.

I've red circled the one that it is in the attached picture.

If all the other bolts are snug to spec, how bad is this? Will it start leaking straight away or should it be ok with the pressure from the surrounding bolts?

I cleaned the heads and everything else very well so the gaskets should have a solid mating surface.

Is there some kind of product I can put on the bolt that could help??

ARG!

View attachment 446905

You will need to do a helicoil here is the kit i used when i had an issue with my lower intake bolt hole being stripped


Amazon product ASIN B082PDTXG4

 

[donalds]

A punch and hammer is my vote

 

[Pete Deering]

A punch and hammer is my vote

? What do you do with them?

 

[Lee's Automotive]

Is the bolt broke off in the hole?

 

[410Fortune]

You for sure need a fastener there, do not put it back together without that bolt or in time it will leak air
I would drill it out and tap it to the next size up, run a slightly larger
Bolt

 

[donalds]

? What do you do with them?

Use this method to unscrew the leftover bolt

 

[usapadyra]

Thanks for all your replies.

I put it back together since I had nothing else to do.

Leak / hiss / was worse than before. Got a knock or two while idling. Turned it off.

Fortunately I have a friend here who has a lot of experience with helicoils - he used to work in a bike shop. He said helicoil plus locktite red should do it.

How can I find out which specific set I need?

Will it safely hold 13 foot pounds?

Cheers

 

[usapadyra]

Is the bolt broke off in the hole?

No. Fortunately the whole bolt comes out.

 

[Lee's Automotive]

Thanks for all your replies.

I put it back together since I had nothing else to do.

Leak / hiss / was worse than before. Got a knock or two while idling. Turned it off.

Fortunately I have a friend here who has a lot of experience with helicoils - he used to work in a bike shop. He said helicoil plus locktite red should do it.

How can I find out which specific set I need?

Will it safely hold 13 foot pounds?

Cheers

Never torque them i just tighten them snug

 

[usapadyra]

Never torque them i just tighten them snug

I was very careful with the top manifold bolts (the torx ones).

Do you really not need to torque the lower intake bolts?

 

[Lee's Automotive]

I was very careful with the top manifold bolts (the torx ones).

Do you really not need to torque the lower intake bolts?

i tightened mine snug and its been over a year with no issue also those torx ones are extremely easy to strip

 

[C420sailor]

I am a torque wrench snob.

That said, it’s recommended here to not use a torque wrench on these. Many report stripped fasteners as a result.

I use a nut driver/torx driver on these, instead of a ratchet. Makes it harder to overtorque.

 

[Josh P]

I am a torque wrench snob.

X2 except I'd use the term a.nal to describe myself. Anything that I think will strip out, I'll stop when it is snug, if it leaks then do a fraction of a turn at a time until it is sealed.

 

[usapadyra]

i tightened mine snug and its been over a year with no issue also those torx ones are extremely easy to strip

I saw in another thread that you have done the same and used a helicoil kit to solve it. Do you remember what size kit you used from helicoil and what the process was? Did you drill it out first? If so, how deep do it drill?

Thanks

 

[Lee's Automotive]

I saw in another thread that you have done the same and used a helicoil kit to solve it. Do you remember what size kit you used from helicoil and what the process was? Did you drill it out first? If so, how deep do it drill?

Thanks

The kit I linked above is what I used and I drilled it all the way through and then inserted the helicoil

 

[usapadyra]

The kit I linked above is what I used and I drilled it all the way through and then inserted the helicoil

So M6 X 1mm is the correct size?

 

[Lee's Automotive]

So M6 X 1mm is the correct size?

Yes that's what i used