header bolts? what does an exhaust leak sound like?

[BerniniCaCO3]

Today I found a loose header bolt. Backed out to the point of finger-loose.
Tightened it back up as best I could, and what I think was an exhaust leak kindof noise got quieter, maybe. Hah.

I was wondering, how do I keep them from backing out? Or did it just back out from heat cycles, since installation on a fresh block (I put headers on in early July), and having retightened it once now it ought to stay?
There is no lockwasher, and, there's almost no room for a lock washer anyway.


Second...
engine RPM and mph are directly tied together.
You know how when you're going up a slope, if you maintain the same speed, and the load isn't quite great enough to go down a gear, the engine will sound different?
I'm just making assumptions, but maybe it adjusts timing, maybe it adds a bit more fuel. What DOES happen when more load is put on an engine, and it has to stay at the same rpm? How does it meet the load?

Anyway, when this happens, when going up slopes without kicking down a gear, I hear what sounds like a lopey cam or a diesel pickup (but quieter of course! Turn the music to a normal volume and you can't hear it).
Is that the sound of an exhaust leak? Why would it make more noise/ this noise when under more load (but not necessarily faster rpms)?
Or is that just a normal sound from dual exhaust?

Tomorrow I might try the tissue paper test to see if there are any more leaks, and check more of the header bolts now that I found one that was loose.
Some of them are SO hard to get to, you'll forgive me if I don't relish even getting a socket onto some of them to see if they're tight already.

[gadget73]

when they keep backing out like that, the headers are probably warped. I used to have those problems with mine, along with popping header gaskets and stuff on a regular basis. Had the headers milled flat and it hasn't given me a lick of trouble in the last 2 years. I have antiseize on my bolts too, so they're definitely not just rusted in place. Short of that, you just make sure you re-tighten them once in a while. Loctite won't work either, the heat will just melt it out.



more load = louder exhuast. the engine is working harder, so any leaks will be more obvious under these conditions. Exhaust leaks can sound like lots of things, including whistles and taps that sound for all the world like a valvetrain problem. Some headers also just make a little bit of noise, not neccesarily a leak, but they sound different than manifolds.


and use a wrench, or replace the bolts with socket key cap screws (allen head bolts). get them from mcmaster-carr or fastenal or someplace, its just a 3/8 course bolt, i think 1 1/4" long or something. Yank an easy to access one out, measure it, and get 16 bolts that size that are easier to access.

[86VickyLX]

Sounds like a ticking that increases with engine RPM. Almost like valvetrain noise. If leaking badly it sounds like a muffler with a hole in it.

[1987cp]

Fancy ARP header bolts with 3/8" heads are FTW if clearance is tight! Wobble sockets can make things easier, and I also own a 7/16" angle-head wrench specifically for getting at standard header bolts on my annoying oval-port Flowtech manifolds.

One thing I like about the stock Mustang manifolds is that there's plenty of clearance for normal hardware-store bolts with 9/16" heads. Also, a lot of people recommend cutting the webbing on "normal" aftermarket manifolds to allow the ports to seal better even if they're noncoplanar to one another.

What sort of header gaskets are you using? I switched to coppers because they're reusable within reason and won't blow out. Very annoying to have a more-conventional header gasket blow out because a bolt came loose, and then you can't get it fixed without having to change the stupid gasket.

Interesting aside - if you buy Mr. Gasket Copperseal gaskets, they come with a set of nice narrow-profile locknuts that will fit even if tube clearance is quite tight. I seem to recall the ARP bolts having a serrated shoulder that doesn't really need locknuts, but I'll have to double check to be certain.

[GM_Guy]

I was wondering, how do I keep them from backing out? Or did it just back out from heat cycles, since installation on a fresh block (I put headers on in early July), and having retightened it once now it ought to stay?

Check them every week if you are driving it regularily, and keep a handfull of bolts in the glovebox when you discover one decided to venture out on an adventure of its own.

Alex.