[Rattiac]

My exhaust manifold on my XJ is cracked.
I can't afford to fix it this year. Other repairs are due. Plus it's quite the project.
What's the best temporary repair. Jb weld, steel stick , etc ?

I can hear a leak during warm up and then goes away.

[sammons]

Rattiac it kinda depends on where and how bad the crack is.  I think JB weld had a high heat that went up to 400-450 degrees. I don't think that would work unless a small crack quite a ways down a long manifold. Probably stink and fall off after a while. 

You can braze a crack to some luck. I usually just v-grind it and grab my wire welder. (I just use .030-.035 mild steel wire). I've welded up cracked blocks (water jacket cracks) and broken exhaust manifolds quite a bit. Most will say it won't work, i just say i didn't know anybetter!  
Problem is usually you will need to pull manifold to weld unless it's out in the open.

On my Ramcharger (before the motor change) my exhaust had a rotted out hole (tight bend) just below the manifold. Temp fix was aluminium furnace tape. Worked  till i swapped motors.

Probably other options out there.

[EDNY]

For some reason I have always had good luck just using my mig welder (solid wire with mix) but I suspect flux core wire would work also.   Repaired cracks on a 78 Corvette stock exhaust manifolds just a couple months ago.  Just weld as much as you can on the car, then remove and finish the welds in "short bursts".

Years ago I had an Izuzu pickup with GM 3.1 engine and the exhaust manifold cracked into two pieces, I mig'd the visible areas, then removed it and welded the rest...it was a temporary fix that lasted over 10 years!

[madmike3435]

my 78 year old friend I call RICK THE WELDER,   pretty sure when he repaired a cast iron manifold for me years ago used a stick welder with cast iron rod with a high nickel content.

Not sure MIG would get hot enough or generate enough power to penetrate properly, unless the MIG was a commercial unit.

Use the right process for the job , guessing and testing others that aren't right will only lead to failure ??

mike............HAIRBALL

[EDNY]

I have stick welded cast iron with specific cast iron rods, you need to heat the metal up with a torch, weld, then keep applying some heat as it cools..you don't want it to cool too fast or it will crack.  But as I said..I have had real good luck (easier) to just use my mig welder with gas mix and just weld about half an inch at a time.

[Rattiac]

Haven't found the crack yet, it has some cooked on mud I'll have to scrape off.
These 4.0ltrs have the shared gasket intake/exhaust.
My last jeep manifold I changed out, I had an exhaust shop put one of those short flexible pipe to eliminate the flex to the manifold under torque to prevent breakage again.

Well, I guess I'll just live with it for now. Maybe next summer I can tackle the project.

[sixball]

My dad taught me to drill the ends of the crack wire brush the crack and braze it with an acetylene torch. It will last for years and never need replacement. Brazing gets a bad rap. It is a great way to stick metal together and it is usually as strong as the metal around it. A problem is it takes quite a bit of heat that can warp a manifold. Best if it can remain it place. I had a 4.0 Jeep that cracked the manifold. Lucky for me it was still under warranty. I Know I still have a gasket around and maybe a cracked manifold. Give me a couple of days to look. Maybe you could repair mine and swap them out. Are there different ones? I've had 3 of those and don't remember which one it was.

[sixball]

That manifold must have gone away or it's in piles that won't gone through till after I am.

[Rattiac]

No biggie. While driving around today the check engine light came on. The code said (misfire # 1 cylinder). Then went out hours later.
I'll probably do plugs and wires . I swear I did that not to long ago.

Muffler came today. 😁
Maybe ill do a header when it's time the replace the manifold next year.

[sixball]

When I had the exhaust done on the '53 several years ago the guy welded a hanger to one of the head pipes in front of the muffler. It came off a year or so later pulling some of the pipe with it. Just too muck stress and vibration. At a local car show I cut up a couple of beer cans and wrapped the pipe and held it on with some hose clamps. Worked fine for a few years. The thin aluminum has now burned through. I'll use something thicker this time. 

[Rattiac]

I found this stuff in the exhaust section. Looked more promising than the other crap I saw, at least it had a temperature rating.
It was only $8 . Picked it up 2 weeks ago but I can't find the crack yet or just ain't looking hard enough.
The exhaust manifold actually looks like a header on it.
Maybe I'll use it, Maybe not. IDK .
Gotta scrap off the cooked on mud first.

[sixball]

The worst that can happen is that you end up with a cracked manifold with that stuff on it. If you wind up taking the manifold off to weld it you gan grind off the magic. There are some really good new products out now. Give it a shot.