New Purchase, Exhaust Manifold Bolt Woes

zealer · April 15, 2014

Hey all,

I purchased a brand used 2000 Silverado 2500 a few days ago, with a 6.0. Outside is kinda beat up, but the interior is nice and she seems to run well. Prior to purchase, I noted that the exhaust manifold bolts would need to be changed on the passenger side (driver side had already been done). Only one head was snapped off, but of course the manifold was leaking right at that bolt. It makes for an annoying sound when driving. I bargained the price of the repair off of the asking price, but it doesn't mean I actually want to spend it at a mechanic!

Today I attempted to replace them, and well, I didn't fare well at all. I must have terrible luck or something, 'cause I ran into pretty much every problem possible when dealing with broken/rusted bolts. I originally just wanted to get the broken bolt out and replace it with a new one, hoping that would seal the leak, leaving the rest in for the moment (if it ain't broke, don't fix it). I bought some nice cobalt drill bits and was planning to drill and then extract it. All is going well, the drill bit is making easy work of the bolt. I pull the drill out to check how far I've gone and notice part of the bit has broken into the hole. Can't drill anymore, great. Looks like I have to pull the manifold off.

I managed to get 2 bolts out easy enough, but then the next 2 would only round. Prior to wrenching on them, I had warmed the engine up (well, I had been driving) and gave them a good dose of penetrating oil (Liquid Wrench). Couldn't get 'em to budge, and they slowly rounded. Now I've got a real mess on my hands. Any suggestions as how I can go about getting these suckers loose?

I may try a larger bit on the broken bolt again, aiming to drill out the broken bit that is stuck inside the first hole.

Also, the canister that hangs off the firewall, is that for AC or EGR? I would guess AC, considering it has tubing that passes into the firewall. Wondering if I can move it out of the way to get better access to the last manifold bolt by the firewall.

txab · April 15, 2014

Time for a professional, based on what you've accomplished so far

zealer · April 15, 2014

I was considering cutting the heads off of all the bolts, that way I could pull the manifold off. I then could have a friend weld a nut onto the protruding edges. Just watched a video of someone doing exactly that, it seemed to work pretty well.

I've considered taking it to a shop to get it done (in fact wil call tomorrow for a quote), but I don't see them doing anything differently than I could do, apart from doing it much faster.

txab · April 15, 2014

If you have the ability then go for it. Removing the manifold should have been step one. Hopefully you can still weld a nut on the broken/drilled stud. Usually trying to drill out a broken twist drill isn't much fun.

Use something other than Liquid wrench next time. PB blaster or Kroil work great. If you were using the proper wrench on the bolt heads, they should have snapped off before they rounded off. That's most peoples experience

zealer · April 15, 2014

I was using a 10mm, 12-pt. I wish they had snapped off, it would be much easier... mind you, once I get the manifold off, I expect to be able to get the broken bolts out either with vice grips or welding a nut on.

I originally did not want to take the manifold off because I figured I would run into a problem like this - the remaining bolts wouldn't play nice. Thus I tried the easy fix of just removing the one broken one. Oh well.

I'm also wondering if I will need a new manifold to fix the leak. It looks pretty warped and I'm not positive that fixing the broken bolt will pull the manifold back down to close the leak (it leaks at the top edge). I'll find out this weekend when I get some free time for attempt #2.

chupe442 · April 16, 2014

I'm also wondering if I will need a new manifold to fix the leak. It looks pretty warped and I'm not positive that fixing the broken bolt will pull the manifold back down to close the leak (it leaks at the top edge). I'll find out this weekend when I get some free time for attempt #2.

Buy a new manifold and have it ready for the project. If you get the old manifold off and it appears level, use the old one and return the new...

zealer · April 19, 2014

Well I finished the job. I managed to find the magical combo of cussing and all is back and in place. In the end I had to cut the heads off 4 bolts (well, one technically snapped off) and remove them with vice grips. Combination of Liquid Wrench, a torch and some serious vice grip muscle got them all out without further incident.

I did not replace the exhaust manifold, just new gasket and bolts. In fact, I did not even remove it completely. I just pulled it out a bit and was able to sneak the vice grips in between the manifold and the head, Leak is gone. Now I've got to find the cause of the ever popular P300 misfire.

Thanks all for the tips.

02suburbanZ71 · April 20, 2014

Hey all,

I purchased a brand used 2000 Silverado 2500 a few days ago, with a 6.0. Outside is kinda beat up, but the interior is nice and she seems to run well. Prior to purchase, I noted that the exhaust manifold bolts would need to be changed on the passenger side (driver side had already been done). Only one head was snapped off, but of course the manifold was leaking right at that bolt. It makes for an annoying sound when driving. I bargained the price of the repair off of the asking price, but it doesn't mean I actually want to spend it at a mechanic!

Today I attempted to replace them, and well, I didn't fare well at all. I must have terrible luck or something, 'cause I ran into pretty much every problem possible when dealing with broken/rusted bolts. I originally just wanted to get the broken bolt out and replace it with a new one, hoping that would seal the leak, leaving the rest in for the moment (if it ain't broke, don't fix it). I bought some nice cobalt drill bits and was planning to drill and then extract it. All is going well, the drill bit is making easy work of the bolt. I pull the drill out to check how far I've gone and notice part of the bit has broken into the hole. Can't drill anymore, great. Looks like I have to pull the manifold off.

I managed to get 2 bolts out easy enough, but then the next 2 would only round. Prior to wrenching on them, I had warmed the engine up (well, I had been driving) and gave them a good dose of penetrating oil (Liquid Wrench). Couldn't get 'em to budge, and they slowly rounded. Now I've got a real mess on my hands. Any suggestions as how I can go about getting these suckers loose?

I may try a larger bit on the broken bolt again, aiming to drill out the broken bit that is stuck inside the first hole.

Also, the canister that hangs off the firewall, is that for AC or EGR? I would guess AC, considering it has tubing that passes into the firewall. Wondering if I can move it out of the way to get better access to the last manifold bolt by the firewall.

Did you get a quote to repair yet? I just had the same problem

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txab · April 20, 2014

Did you get a quote to repair yet? I just had the same problem

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He did the work himself

zealer · April 20, 2014

Yes I did it myself. $33 all in for gaskets and new studs. Probably took me 5 hours for one side. Extracting the broken studs is very time consuming. An experienced mechanic would be able to do it quicker (I feel like that if I had to do it a second time I would be much quicker, knowing what I know now)

I would suspect a shop would charge no less than $400 because it is highly likely they will run into similar problems as me (rounded and rusted heads, snapped off heads etc) which are just a pain and time consuming to deal with.

02suburbanZ71 · April 20, 2014

Is it worth upgrading to LT's if i have the same issue on the driver side?

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zealer · April 21, 2014

Depends what goals you have in mind for your truck. LTs not going to hurt, but will cost more (higher purchase price). If you want some added performance and your budget allows for it, LTs are great. You may have to make further modifications aft of the headers though if you want LT's to fit. I'm not very familiar with these specific vehicles yet.

I never took my manifold off completely because I was unable to. The manifold to pipe studs (pipe going back to the cats, can't remember if it has a specific name) were so rusted on my truck there was no way they were coming undone (I tried). Same with the EGR bolts (passenger side only). If I wanted to get the manifold off, I would've had to cut it off and replace it, and replace the lower joint as well. Therefore, I used cargo tie down straps to pull the manifold out giving me enough room to slip vice grips in between.

For my needs, I wouldn't have installed LT's even had I got the manifold off. I don't want to spend the extra dough for them. But that's me, every case is different.

Hillger 189 · April 22, 2014

Snap on makes the best extraction kit, if it's gonna be something u use in a weekly or daily basis I'd look into it ( for extracting threads and stripped bolts) if for some reason that dosnt work then I'd goto Home Depot or lowes and get heli coil and completely drill them out And re thread.