Exhaust Manifold Bolts

[oldchev]

I get lazy (or maybe it's the pain) as I get old. Slowly, my 04 Yukon 6.0 Denali has been breaking exhaust manifold bolts. Now 3 on drivers side (two farthest back) and the rearmost on pass side. Total of 4.
It only makes the exhaust (ticking) sound when cold, so I let it go. Well now (in CA) it wont pass the smog inspection (they say). It did pass the emissions test. Overall...FAIL.

I left it at the shop for an estimate today. I hate to do that, so just the estimate. I'd love to hear about others experiences for removing these broken bolts, doing the DIY on their own. I have watched the videos, selected specific penetrant, ordered a new bolt extractor, and yet to order new bolts.
I see a bolt kit including gaskets for manifolds, and the Y pipe metal "O" rings. The Y pipe was off two years ago so I know it probably will come loose again easily (with penetrant). I used my borescope to see, and did measure the depth of the break. They are all 1/8-1/4 deep into the manifold. That would leave the remaining bolt accessible after manifold is removed. I'll bet other bolts will break as they are removed.

I don't plan to keep this much longer so didn't want to get into $$$ for someone else to repair but it has to pass smog in CA to sell. It's been a good vehicle and I've had it since '11, now with 298K.

 

[DoubleDingo]

I've read that using wax frees up stuck fasteners better than anything. Heat it up, let the wax wick into the threads, and comes out easily. Haven't had to try the method, but will if I run into that situation.

 

[Fless]

ARP makes good manifold bolts.

 

[Joseph Garcia]

Be sure to use ARP bolts to replace your existing broken ones. You won't see them break again.

 

[justirv]

I've read that using wax frees up stuck fasteners better than anything. Heat it up, let the wax wick into the threads, and comes out easily. Haven't had to try the method, but will if I run into that situation.

I need to look up this technique.

 

[strutaeng]

I think if you remove the wheel liner, then access becomes much easier, relatively speaking.

I've used the weld a nut method with good results before, but on engines I had on hoist or heads on the bench. My 06 Suburban had a broken bolt, and to my surprise, had about 1/4" thread outside when I removed the manifold, so I just spun it out with vice grips.

 

[Scottydoggs]

no matter who does the job, id use studs. they dont break or fall out.

 

[PG01]

I've read that using wax frees up stuck fasteners better than anything. Heat it up, let the wax wick into the threads, and comes out easily. Haven't had to try the method, but will if I run into that situation.

I need to look up this technique.

Some guy by me swears by crayons…. Not even kidding i never tried it tho

 

[justirv]

Some guy by me swears by crayons…. Not even kidding i never tried it tho

Well, I am a Marine, so I should know something about crayons. I'll check it out.

 

[oldchev]

A follow up. The shop bid was $2346. That's right. There is No Way I'm paying that much.
I saw a great video on YouTube. Take out the inner fender for access. Drop the Y tube, and so on.
Just another thing. I'll start this job in a couple weeks. I plan to take notes and pictures of my process, and progress noting any pitfalls for all to learn (if you need it). I have the tools. I have the motivation. Let's do this.

 

[ncampion]

What's the downside to using good stainless steel fasteners for exhaust system? No corrosion.

 

[John H Daniel]

I used Kral Auto Parts manifold bolt repair gadgets. Not too hard to install, stopped the clicking, no leaks.
They attach to existing bolt holes; ~$40 each.

 

[Tonyrodz]

A follow up. The shop bid was $2346. That's right. There is No Way I'm paying that much.
I saw a great video on YouTube. Take out the inner fender for access. Drop the Y tube, and so on.
Just another thing. I'll start this job in a couple weeks. I plan to take notes and pictures of my process, and progress noting any pitfalls for all to learn (if you need it). I have the tools. I have the motivation. Let's do this.

They must have some good dope there.

 

[houstontaylor]

It's good you're replacing the bolts for the next owner. I used to get very sleepy at times on long trips and had to stop to recover every so often. Then I checked the exhaust manifold bolts and found they were all loose. I think I was getting carbon monoxide in the cabin.

 

[Scottydoggs]

What's the downside to using good stainless steel fasteners for exhaust system? No corrosion.

any time you put two different types of metal together you will get corrosion. thats the down side of AL heads.

also why i like studs better, put the stud in and its there for life if all goes well, the stud is using every last thread in the soft al head threads, and once you put the nut on you can just tell its way tighter then a bolt, that had to pull its way through them threads to get tight.

 

[Fless]

What's the downside to using good stainless steel fasteners for exhaust system? No corrosion.

FWIW depending on the grade of the stainless steel, the metal can be weaker than standard bolts.

 

[DoubleDingo]

Some guy by me swears by crayons…. Not even kidding i never tried it tho

Yep, I've heard the same thing. Heat it up gutenhot! and melt the wax/crayon on the threads and let it wick

 

[Bentawrench0r2]

I've used beeswax candles on large broken bolts on heavy equipment. They come loose, prolly because of rosebud torch tip size of my thumb rather than the wax. For the exhaust bolts if a little thread is out past the head jam a hex nut over it and hot tack it with a wire feed welder. Heat expansion & cool off will loosen it, spin out easy. If it's broke off inside best luck is one of these Lisle kits for LS exhaust bolts. Best $100 I spent doing first LS swap! https://www.jbtools.com/lisle-71400...fgn0V8R-vroBXB_0FSLjbc7Sxc8nUNrBoCG7MQAvD_BwE

 

[Jason Sewill]

I just did all of mine. 7 of them broke off. 4 inside the head. PATIENCE is the key.
Put it up on jackstands. Remove front tires and fender wells. Drop the exhaust. Remove exhaust manifold bolts. If they turn just a MM….its a good day. Lots of penatrating lube. Work back and forth. More lube. Back and forth. And on and on. No more than 35lbs of torque or risk breaking them. It takes time but if they move at all….they will come with patience.
Broken ones………
If you can get on them with a vise grip….same senereo. If you cant, drill them starting with a small pilot hole and work your way up as far as you dare. Then i used a cheap set of Irwin extractors useing the same method. All but the drivers rear one came out as i broke a bit in that one. Hint…drill slow, dont force,let the bit cool after a few seconds. You will need a 90 degree milwakee bit holder for the back 2 bolts.
The one i broke a drill bit in…..I had to revert to the welder technique which i dont believe in. However it is the quickest way but i believe the extreme heat weakens the threads because aluminum melts at a much lower temp than steel.
LAST TIP………
Do NOT use bolts or stainless steel anything. Use 8mm(i believe) STUDS and NUTS to replace the old bolts. Torque to specs. Studs and nuts work much better than useing just bolts because of the heat expansion and contraction. Not gonna get into the physics of it but its the best option.

 

[TxVet33]

no matter who does the job, id use studs. they dont break or fall out.

who makes the best studs? Thx.