Greetings,

I use my 08 'splorer Ltd with 4.6l primarily for towing a 6000 lb (true weight) trailer. I tow about 2500 miles per summer, and drive it about 2000 miles the rest of the year. a low-use vehicle.

The upper exhaust manifold bolt from the #1 cylinder is missing.

https://picasaweb.google.com/lh/phot...eat=directlink

My guess is that it was there when I bought the vehicle In April of last year with 63k miles on it and it snapped off sometime since. Now I have 67k on it. And of course I hear the tick tick tick at cold start up. It goes away after 45-90 seconds depending on ambient temp.

Looked at the job. Though fairly mechanically inclined, I don't want to do it. Very close quarters, I have no lift to speak of, snapping more off, drilling, chance of water jacket perforation. All of this adds up to me not wanting to do the job. That said, I don't want to pay a buttload (dealer) to have it done either.

The only way I would consider repairing this is if I KNEW for certain what the underlying cause was and that it was fixed before going through the trouble of removing and reinstalling the manifold. No one seems to know what the root cause is. Defective manifold? Bolts? Head? poor assembly skills? etc.

My main question is: What is the risk if I do nothing? Will it get worse? How much worse? Will it cause any FURTHER damage? What are the consequences of doing nothing?

Thanks.

 

Heat failure or poor install (not torqued correctly) are the usual causes of snapped exhaust manifold bolts.
You risk the manifold warping, the gasket blowing out...

consequences will be illegal air entering the exhaust,
causing the O2 sensor to register a lean condition,
then PCM will increase the injector pulse to obtain stoic (14.7/1),
to fuel rich miss fire.
finally rich condition in exhaust manifold and CAT,
CAT over heating and melting....$$$$$$..... Philip

 

Have you confirmed if the stud is snapped or if it just happened to back out? If it just backed out, you can probably chase the threads and install a new stud.

I attempted to help a friend replace some broken manifold studs in his F-150 with the 5.4L and we got out all but one of the studs. The one we couldn't get happened to the upper rear corner on bank 1. We couldn't get to it with my shallow right angle drill and stubby bits and I wasn't able to get anything welded on to the stud to turn it out. It was about a thread below the head surface. He ended up taking it to a shop where they removed the head and milled the broken stud out.

-Rod

 

Just curious if you resolved this and how? I have the exact same problem on my 2006, same bolt, etc.

Thanks

 

Anothersteveg,

No I have not taken any action with mine. Though I just read the previous post and it never occurred to me that it may have broken off and just backed itself out. It is very difficult to see in there. When the weather gets warmer, I may pull the inner wheel well and see if I can get a better look and see if in fact, the bolt is still in there. If not, I may consider putting one in. I have been told that the inside of the bolt hole at the end, is very close to the water jacket and easily cracked.

Anyone?

 

Mine definitely broke, I can see the end of it. The shock tower makes it hard to get a good look at it, or a straight shot with a drill for that matter. I've tried a right angle drill but even that is hard to get lined up. I'm basically out of ideas and am going to have to take it in to a shop. I can't see any way to do it without pulling the heads.

I'm open to ideas though if anyone wants to chime in.

Edit to clarify: I've already pulled the manifold. The other 7 came off no problems. I tried drilling out the middle and using an EZ out, but it only comes out so far. Feels like the threads are messed up about where the bolt broke and it won't back out any farther. I can't get a bigger bit in to drill it out completely, and even if I did I can't see how it's possible to tap new threads with the limited space.