6.0 Exhaust Manifold to Head bolts broken.

Grubbworm · March 13, 2023

I have 4 broken exhaust manifold to head bolts broken. One on the driver's side and three on the passenger side. From what I have read this is a common occurrence for this engine. All but the back one on the driver's side were protruding from the heads. I got all of those out with minimal issues. Now I have to move on to the difficult one in the last rear hole on the driver's side. That one is broken off inside the head, just below the surface.

The heat wrench and air impact gun helped me remove the exhaust flanges. Kroil helped me remove the exhaust manifold bolts that were still holding the manifolds on. I have purchased some stainless steel bolts from RockAuto to replace them all with.

I have been working on this all weekend. I had the passenger side ready to go back together and ended up snapping the head off of the last stainless bolt in the rear. Now I have to take it back apart and start all over again.

I will measure the new and old bolts to see if they are the same length.

Well the new bolts are 30.7mm and the old ones are 30mm. I guess I will order some different new bolts that are 30mm. The new, new bolts are not stainless, but do have a corrosion resistant coating. I think I will use a tap and chase out the threads on the heads also.

As for the Driver's rear broken bolt, I think I will try to weld a nut on the end and use some heat on the head to get it out. We will see if that works.

Edited March 13, 2023 by Grubbworm

davester · March 13, 2023

I just got grade 10.9 flange head bolts when I did my exhaust manifold bolts.

If you can't get that back bolt out, you might consider getting a clamp to hold the manifold in place. The clamp bolts to the head using existing, unused threaded holes, and then you install a bolt that presses against the manifo to hold it again the head. There are 2 different clamps available, depending on which end of the head it mounts on.

Formulabruce · March 14, 2023

On the DS rear, buy a bracket that bolts to the back of the head, and has a bolt that puts pressure on the manifold at the original hole and it will Not leak. These are all over Ebay. Its tough to get back there to install it, but it works.

On the Bolts, Im with Davester, But I use COPPER never seize as well on them. Don't use aluminum never seize on Aluminum heads, you need a dissimilar metal.

David89GMC · March 14, 2023

Yes, tough job. Get ARP bolts, use antiseize, and look on youtube for different methods for removing the bolts. Some use Mig welding, if you happen to have a Mig welder. Just weld a bolt, or something, onto the broken bolt and unscrew.

carkhz316 · March 17, 2023

On 3/13/2023 at 9:26 AM, Grubbworm said:

I have 4 broken exhaust manifold to head bolts broken. One on the driver's side and three on the passenger side. From what I have read this is a common occurrence for this engine. All but the back one on the driver's side were protruding from the heads. I got all of those out with minimal issues. Now I have to move on to the difficult one in the last rear hole on the driver's side. That one is broken off inside the head, just below the surface.

The heat wrench and air impact gun helped me remove the exhaust flanges. Kroil helped me remove the exhaust manifold bolts that were still holding the manifolds on. I have purchased some stainless steel bolts from RockAuto to replace them all with.

I have been working on this all weekend. I had the passenger side ready to go back together and ended up snapping the head off of the last stainless bolt in the rear. Now I have to take it back apart and start all over again.

I will measure the new and old bolts to see if they are the same length.

Well the new bolts are 30.7mm and the old ones are 30mm. I guess I will order some different new bolts that are 30mm. The new, new bolts are not stainless, but do have a corrosion resistant coating. I think I will use a tap and chase out the threads on the heads also.

As for the Driver's rear broken bolt, I think I will try to weld a nut on the end and use some heat on the head to get it out. We will see if that works.

The new bolts were probably just fine. an extra .7mm didn't bottom out in the cylinder head. I'm guessing you overtightened them or were just unlucky. The torque spec is only about 18ft.lbs. As far as removing the broken ones, if you have access to a welder, do as David89GMC said and weld them out. This is what I do as its far easier and quicker than most of the other methods, and allows you to fix the problem properly.

On 3/13/2023 at 9:22 PM, Formulabruce said:

But I use COPPER never seize as well on them. Don't use aluminum never seize on Aluminum heads, you need a dissimilar metal.

Copper is fine, but so is aluminum anti sieze. Its dissimilar metals that cause galvanic reaction (steel bolts in aluminum cylinder head), so I'm not sure where you got the idea that you can't use aluminum anti sieze on aluminum parts.

On 3/13/2023 at 11:09 PM, David89GMC said:

Yes, tough job. Get ARP bolts, use antiseize, and look on youtube for different methods for removing the bolts. Some use Mig welding, if you happen to have a Mig welder. Just weld a bolt, or something, onto the broken bolt and unscrew.

Seconded on welding them out. This is the way.

Grubbworm · March 20, 2023

Okay, so I have been sick for a week and have not been able to work on the truck. I got back to it on Sunday. And, with a little help from my son, we were able to get both of the stuck/broken bolts out. We did use a 110v cheap welder on the driver's rear broken bolt. It took him more than several tries to get it to work properly. In his defense, the welder has been sitting in storage for more than 20 years and the cable was all twisted. Which did not allow the wire to feed properly. But he finally got it to work enough to get the job done.

I started putting the passenger side back together and it is mostly done. Next up is the driver's side prep and reassembly. Using copper anti-seize and new Fel-Pro coated bolts.

Grubbworm · April 13, 2023

Ok, this job is finished and no more exhaust manifold leak sounds. Also, all of the broken bolts have been replaced along with the non-broken ones. Also, new Mahle gaskets. Now on to the next project.