Exhausta manifold crack (What material is for welding)

My jeep es a Cherokee 99, 4.0 L. The exhaust manifold cracked, i thing is easy to fix but I want to know how that material it is, to be able to apply the correct weld.

Thanks.

JB of course! jb weld man! hahahaha. actually i have no idea.

Do a search for cracked exhaust manifold,
I found a source here and got a new one for less than $100.00 shipped.
If you weld it, it will crack again.
Besides, it is p'rolly broken it several pieces, the one I changed was cracked three places, and you will have to rip the heat sheild off to get to the crack.
Don't buy a used one, chances are it will be cracked also,
guess how I know that.

It may not be quite so easy to find one in Panama. I think mine may be cracking too, and although I know all the caveats, I'd sure like also to know if anyone has an idea what the best material or technique would be for welding it. Because not to put too fine a point on it, for my poor old thing which just turned 240 thousand miles, still hasn't had its main seal replaced, still hasn't had its howling rear end replaced, and still has rust holes not only in the rockers and floors but even in the cargo compartment and the roof, it's either weld or nothing.

These will crack again right away

It's not mild steel, so if it's welded with steel filler will most likely crack again. I think it's stainless filler you need, a TIG repair should be fine.

I got a couple to hold for around three years, before they cracked again. The new replacement cracked again in four.
I haven´t treid it, but a friend (who knows his stuff) recommened silver solder, if the crack hasn´t spread to much.
I used a MIG and made a series of spot welds, to keep the temperature down. Sprayed the header while welding, with a light coat of water (with a window pump sprayer) also to keep the temperature down. Found a big piece of 3/8 flat steel and "C" Clamped it in numerous spots, to help prevent warpage. The first one I welded, almost wouldn´t fit back on the head, it had a bow in the middle and the bolt holes didn´t line up real well,
When I was done, I heated the metal around the weld to around 400 degress and slowly reduced the heat (backed the torch away from the area).
If it´d cracked down around the collector, I wouldn´t even mess with it and just buy a new one.

ive never really looked at my exhaust manifold on my XJ....

i know with other cars they have been cast iron.... but not sure on the XJ...

if it IS cast iron, at the end of the crack on each side, drill a LITTLE hole to stop the crack from spreading then go nuts... ive successuflly welded MANY exhaust manifolds like this and have never had them re-crack...

JOe

If you know how you can braze cast iron and it will hold pretty well. Find a welding shop they can preheat it then braze it. They might even be able to weld it with cast iron rod. Not that many that do that process.

4.0 manifolds aren't cast iron. They're all tubular style from the factory. Take a look.

KingOfTheHill said:

ive never really looked at my exhaust manifold on my XJ....

i know with other cars they have been cast iron.... but not sure on the XJ...

if it IS cast iron, at the end of the crack on each side, drill a LITTLE hole to stop the crack from spreading then go nuts... ive successuflly welded MANY exhaust manifolds like this and have never had them re-crack...

JOe

Click to expand...

As noted elsewhere it's not cast iron, but I have wondered if the drilling would work on tubular steel cracks as it does on cast.

Drilling the hole relieves the point of stress, preventing further spread and works in most metals.

I was thinking the same thing about repairing the further cracking of the header, its been repaired once. Its not stainless tube, not mild steel either. I would a small hole in each end of the crack. These tubes warp a lot when heated, you can tell how much the crack closes when the engine is hot. I would either weld a mild steel plate wrapped around the crack or braze it. I was thinking about gas welding it, to avoid processes that overheat the material, don't stick weld it. Of course I'm no expert but brazing seems better, you heat the metal white hot (not melted) and apply a bead of flux-coated brass rod. Its easy, it adheres strongly. Before you posted this I wanted to see how brazing it would work so I tested a piece of steel plate I broke. Notice the metal is bent, I bent it after welding it so you can see the metal bends before cracking the weld. BTW, the brass ran so much because I used a pipe soldering torch and had to hold the connected tank with one hand. It would look better with a proper torch but it did the job. Anyone know why these break so much?
http://img23.echo.cx/img23/5345/img06804jv.jpg

Has any one here used quick steel to temp. fix the crack instead of welding it?

Clean it, weld it and put in a section of flex pipe that replaces the section that runs crossways.

Or buy a new one, but still put in the flex pipe.
It relieves the stess of a rigid exhaust on the manifold.