I've looked around this forum for a bit but couldn't find anyone else talking about this specific problem.

2006 SLT w/ 4.7L V8

I think one or more of the bolts holding my exhaust manifold on have rusted through and broke off.

I started to hear the "tick tick tick" sound one day and figured it was my passenger side manifold leaking. I take a look and realize that one of the bolts is just kind of dangling... still on there, but definitely doesn't seem intact. It was covered in rust so I assume it rusted through and broke? Wondering if any of my other bolts are in the same condition, I put my finger on the bolt next to it and it seems to "snap" and start dangling like the first one.

Has anyone else had this issue? Is it possible that the bolts did actually rust through and snap off, leaving the threaded portion still in the engine block? Would a mechanic have to remove the engine to drill out the holes and fix it?

Trying to figure out as much as I can before I take it to a mechanic... I'm dreading the bill. Any help is appreciated.

 

yup, the studs break. it doesn't require an engine removal but it is kind of a pain to get the broken bolts out especially if they are flush with the block. they would use a left handed bit or an ez-out and repair the threads if necessary and maybe use a helicoil. all the hardware/gaskets need replacing

 

Very common on the 4.7. Mine snapped around the 80k mile mark. Was a fairly easy repair for me. About $50 in parts IIRC.

 

There are other threads on this forum that talk about exhaust manifolds and broken bolt removal - check them out using the search feature.

I don't recommend getting the bolt drilled out - you NEVER get the new holes on center or straight, so then you need to drag holes in the manifold to make things fit. The hole dragging weakens the manifold at that point where it can break. There are some good methods of removing the broken bolts/studs by using a welder, I described this approach in a recent thread.

My advise would be to ask how the mechanic would fix it & if he tells you that he's going to drill - move on to the next mechanic with the same question.

 

The most common problem, which I had, was the heads of the bolts are snapping off. But that is good because I could use locking plyiers to twist the bolt out. I took advantage of the effort and put some nice headers on instead. They came with new hardware to mount. Easy job..seems like a common 3rd generation problem.

 

when putting the manifolds back on. 1. do NOT use cad plated bolts. the plating will come off and jam the threads. 2. DO use anti-seize compound on ALL threads 3. on the first install torque the threads to only 70-80 % of full torque. then after 5-6 full temp cycles take to full torque. if they start to leak before that go to full torque. 4.. on flange to flange on a pipe use the largest bolts that will go in to the hole.

 

This is probably a dumb question...but when that happened, was detecting it as simple as looking at the manifold and seeing the bolt heads missing?

 

Yea, I'll bet The problem is on the passenger side. With a flashlight, see if you can notice the bolt heads or just the smooth bolt missing the head. I removed all the remaining bolts except for the one that snapped. I then pulled the exhaust manifold straight off and got that 1/2 inch access to the snapped bolt . Luckily I could then just twist it out by clamping down on it with vise grips. 6 mos ago I did a search on these forums and someone had a pic of the snapped bolt, looked just like mine. I imagine that I could have just replaced the gasket and purchased news bolts which would have solved the problem. The manifold was undamaged, it was just a missing bolt that causing a gap letting the exhaust escape. When the engine heated up, the noise would dissipate.