Exhaust manifold bolts

[NJTB]

Recently I chased down an exhaust leak on my 04 LS. It turned out to be a cracked manifold, and I took it off. Luckily only one bolt broke and I managed to remove it with a minor struggle. After I was done with the removal, I came inside and checked all the posts on the aforementioned problem.
After spending alot of time reading, there were some posters that used never sieze on the manifold bolts instead of locktite, which is called for. Having spent way too much time with galled threads from aluminum-steel contact, this had my attention.
So my question is, has anyone tried it and does it work?

 

[Mounce]

I've seen multiple people swear by putting anti-seize on bolts like that where that the bolt is steel and is screwing into aluminum. If your bolt would've broken off inside the block and required drilling and re-tapping, I don't think you'd question it. (you said you removed the bolt with minor struggle so I'm assuming it didn't break inside the block.)

 

[Texan]

Using anti-seize on steel bolts in aluminum has been recommend for many years.
I have not had this problem yet, but if I did I would use anti-seize.

 

[NJTB]

I've seen multiple people swear by putting anti-seize on bolts like that where that the bolt is steel and is screwing into aluminum. If your bolt would've broken off inside the block and required drilling and re-tapping, I don't think you'd question it. (you said you removed the bolt with minor struggle so I'm assuming it didn't break inside the block.)

Yes, the bolt head snapped off and left about 1/4 inch sticking out of the head. It was too short for stud pullers or vice grips, but on a trip to the store I found a screw extractor that I hammered on and managed to remove it.
My big concern is the factory used loctite, I don't want to cause a problem where I'm tightening the manifold every six months using anti seize.

 

[BlazingTrails]

I put anti seize on mine, going on 10,000 miles with no problems.

 

[NJTB]

Anti seize it is-and I hope I'm not out in the driveway in January tightening the manifold. The part should be here in a few days, I'll post back.

 

[808_LS_EXT]

Anti seize it is-and I hope I'm not out in the driveway in January tightening the manifold. The part should be here in a few days, I'll post back.

I'd rather have to re-tighten manifold bolts than drill them out of the head the next time the manifold cracks(which apears to be a recurring problem).

I rocked my bolts back and forth (1/2 turn out, 1/4 turn in) while I was pulling off the manifold. I ended up with zero broken bolts.
I did replace 4 bolts which appeared weakened, and applied anti-sieze to all of them upon reinstallation.

Did your manifold look like mine?
I bet I'd win a contest for the largest "crack".....

 

[Mooseman]

Wow, that is bad. Much worse than the two I dealt with. For the bolts, I replaced all of them with high strength metric bolts. I have a feeling that they used torque-to-yield bolts, which have a high breakage rate like the head bolts.

 

[NJTB]

I replaced the manifold last week. Nothing spectacular, took my time, made sure everything was cleaned up and ready to go. The manifold arrived in good shape, the gasket had slight damage (shipping). I straightened it out and used it. Other than that it was a straight forward replacement.
I did have to use my 3/8 drive torque wrench (set at 220 in. lbs.) as the 1/2 inch drive was too difficult to maneuver in the space. Loaded the bolts up with anti-seize, made 3 passes with the torque wrench (10, 15, 18 ft. lbs) and continued on.
The only problem I had was with the exhaust donut. After assembly, there was still a slight leak at the donut. The trick turned out to be-hold the pipe up to the flange, making sure the two flanges are seated, put the collar on and hand tighten the bolts, wiggling it a bit to be sure it fits together tightly. Then tighten the bolts EVENLY. No more noise, I'm happy.

 

[NJTB]

I'd rather have to re-tighten manifold bolts than drill them out of the head the next time the manifold cracks(which apears to be a recurring problem).

I rocked my bolts back and forth (1/2 turn out, 1/4 turn in) while I was pulling off the manifold. I ended up with zero broken bolts.
I did replace 4 bolts which appeared weakened, and applied anti-sieze to all of them upon reinstallation.

Did your manifold look like mine?
I bet I'd win a contest for the largest "crack".....


That is quite the crack.
No, mine was cracked on the inside toward the engine. I googled some pictures and one of them had the exact crack in the same spot.

 

[PProph]

I haven't been able to get any of my bolts to budge yet. I'm really not sure what to try, I know a guy with an oxy-acet torch but I think he's avoiding me for the size of the job haha. I've used the acetone/atf mix on all the bolts several times, but I'm scared to put much torque on anything for fear of breaking heads off. I just called a local dealer for a quote and was given minimum 450 assuming none of the bolts break. I know they won't take care with it and that 450 will turn into 2 grand.

Could I try heating the bolts with a regular propane torch or would that not heat them up enough? I've had my TB parked far too long this year and I'm tired of borrowed vehicles, my frustration is at its peak.

 

[808_LS_EXT]

I haven't been able to get any of my bolts to budge yet. I'm really not sure what to try, I know a guy with an oxy-acet torch but I think he's avoiding me for the size of the job haha. I've used the acetone/atf mix on all the bolts several times, but I'm scared to put much torque on anything for fear of breaking heads off. I just called a local dealer for a quote and was given minimum 450 assuming none of the bolts break. I know they won't take care with it and that 450 will turn into 2 grand.

Could I try heating the bolts with a regular propane torch or would that not heat them up enough? I've had my TB parked far too long this year and I'm tired of borrowed vehicles, my frustration is at its peak.

IMHO, heating the bolt expands the bolt and makes it even tighter in the aluminum head...

Essentially, what you want to do is heat the outer, which in this case would be the head, which you can’t do.

There's a lot of metallurgy to understand when you attempt heating a steel/aluminum connection.

With that said, I'll share how I got mine out.

First, I attempted the bolt that would be easiest to access with a drill if it broke, which is #2 & #3 cylinder.

I then turned it out 1/4 till it felt like it started to bind, then turned in back in.

I did this a few times, then turned it out 1/2 turn.

Then started the sequence of 1/2 turn out, 1/4 turn in, until the bolt felt free enough to spin out.

Continued on to #2 & #1, then once confident with the sequence, I moved towards the #5 & $6 cylinders.

It took some patience, but I was able to remove all bolts without heat and without breakage.

Do not re-install the bolts without inspecting them. Replace the weakened ones… better yet,
Buy a whole set of replacements…. And put anti-seize on the first ½” of the threads.

 

[PProph]

I did in fact buy entirely new bolts. I guess I'll have at er again, I just wasn't getting any movement at all. I did a lot of research here and on the OS, I definitely know about the back and forth, but the most success I saw was with heat. If I could budge any of the bolts even the 1/4 turn or an 1/8 I'd be a little more confident. I do appreciate the help though.

 

[808_LS_EXT]

I had a plan "B" , in case the bolts would not turn out.

It entailed removing the intake duct and O2 wire to remove the heat shield,
then re-install the intake and O2 Wire.

Warm the engine up, then try to turn the bolts out while the head was still hot.

Fortunately, I did have to execute plan "B", but you may want to try it.

 

[808_LS_EXT]

Also, once you get the bolt to turn even a little, spray some PB Blaster between the manifold flange and head, then turn the bolt back in...repeat, repeat.

Eventually the PB Blaster will penetrate its way into the threads,,,

 

[808_LS_EXT]

Click this link to see what I had to do to fix an
Exhaust Manifold Gaket Leak on a Dodge Ram...

 

[PProph]

I should mention the purpose of the heat is not the expansion of metal but rather the softening of the threadlock used on the bolts.

 

[Mooseman]

And also burn off the corrosion. When I swapped engines, three or four were already gone off of the new engine (maybe the yard tried to take them off or they popped off by themselves). Only very short stubs remained. I heated them with the torches and they came out like butter.

 

[PProph]

I'm assuming a higher heat torch though?

 

[Texan]

If you can use a MAPP gas cylinder on your propane torch, you can get a hotter flame.

 

[PProph]

mostly success, got it off, must be the luck of the day. one bolt broke though but no amount of heat would have changed that. of course it's the furthest back and hardest to get at, gonna try to drill it out.

 

[Mooseman]

Try heating it with the torch and try to turn the stump with pliers or something. That's how I got my broken ones out.

 

[808_LS_EXT]

mostly success, got it off, must be the luck of the day. one bolt broke though but no amount of heat would have changed that. of course it's the furthest back and hardest to get at, gonna try to drill it out.

Congrats!

How much of a nub on that broken one?

 

[PProph]

no nub, it's broke down into the hole. tried drilling out today with no luck, got some advice from my guy and some tools, gonna have at er again tomorrow.

 

[NJTB]

no nub, it's broke down into the hole. tried drilling out today with no luck, got some advice from my guy and some tools, gonna have at er again tomorrow.

Did you ever get the bolt out?

 

[PProph]

Cold weather put it on hold as I have no garage to work in. I'm taking it over to my car guy this weekend, we'll get it out.

 

[PProph]

took a lot of work but it's out today. i'm back on the road. had it towed this morning, sad sight. drove it home though, happy sight. we ended up damaging the threads enough getting the bolt out that we went with a heli-coil to put that last bolt in, it's all good though.

 

[BlazingTrails]

Nice man, glad you got it going!