Exhaust manifold leak question

[alrock]

Well, we figured out my exhaust manifold leak today. It isn't at the gasket, as it most common and abntroop just had fixed. It's a large, long crack above the catalytic converter. Caused by the POS installation of my aftermarket exhaust that constantly droops, flexing the exhaust manifold.

So, a new exhaust manifold is $450-$500 plus labor. Can the crack be repaired?

 

[ABNTROOP]

I don't think so, some might say JB weld, etc but the exhaust manifold expands and contracts quite a bit due to heating and cooling, and I'm not familiar with anything which could handle the heat or be able to expand and contract with the manifold. Best bet is to do it right and do new manifold, new gasket, and important! New bolts! Which side btw? Drivers is cheaper than passenger, and once you remove the fender wheel well lining it seems to be a pretty straight forward process. That being said, if you do it yourself, soak all those bolts with liquid wrench before trying to remove the manifold to avoid having one shear off like mine.

 

[alrock]

The fortunate thing is that on an I5 there's only one exhaust manifold

 

[ABNTROOP]

LOL! (Forehead slap) wasn't thinking, so not a clue for the I5 as far as accessibility.

 

[Mr_Rich]

I tried posting a response with my BB earlier and it dropped off. I'm at the gf's comp this time. Magnaflow has a 49-state manifold/ cat converter to replace the exhaust manifold on our I5's. If I lived in AZ or the Northwest I'd probably install one on my truck. The Magnaflow manifold looks like a tuned exhaust header for the I5.

 

[alrock]

Nice to know there's performance alternatives like the Magnaflow, but at $705 I'm not sure that I'm going to get that spendy with 128,000 miles already on this engine.

 

[ABNTROOP]

So how many miles until you sell your H3?

 

[twinmill28]

Oh he won't be selling it, you need to be watching for an engine swap thread for a little four banger diesel. You gotta remember Alex is in Az and knows people who know diesels.
This oughtta be good....

 

[Schwarttzy]

Hopefully I'm not hi-jacking the thread too much, but I swear I can hear my exhaust making a ticking noise. Is there any things that normally go wrong with our I5 exhausts? I'm starting to get the point where I'll crawl in there, but it would be nice to have better guess before I start.

 

[alrock]

I'll be keeping the H3 for a long time. I doubt diesel will be the way I go, due to the more complex installation and the local emissions laws.

Schwarttzy, it's not uncommon for the H3s to break exhaust manifold bolts. That could be the source of the ticking noise.

 

[ABNTROOP]

Usually is! So just a motor rebuild when the time comes alrock?

 

[SuperBuickGuy]

Yes, you can weld cast iron. I do it all the time. Key is heating the part to 400 degrees, and welding with either cast-iron arc welding rods or welding with stainless wire in your MIG welder - then letting it cool as slowly as you physically can (bury in sand works well). Of course, it goes without saying that the crack must be clean and free of contaminants.

 

[alrock]

Usually is! So just a motor rebuild when the time comes alrock?

Nah, something between a 5.3 to 6.2 at that time

 

[telemike]

http://www.jagsthatrun.com/Pages/Parts_COL-headers-Shorty_5-Cyl.html