Cracked exhaust manifold

Bullet3600

Bullet3600

New member
1056625

I have about a 2 inch crack on the top of the exhaust manifold near the back above the donut gasket. I can reach it when I remove the heat pan on the intake, My question is what can I use to seal the crack w/o going through the mess of replacing it. I have used liquid steel and JB weld on it and both sealers just burned off. I'm just wondering if anyone has had any luck using a high temp sealer on an exhaust manifold in the past :-( ...............Bullet[addsig]
 

1056627

seriously, i would try just using a stick or mig welder and putting a bead-weld over the crack. exhaust manifolds get too HOT to use JBweld or whatever... exhaust coming out of the combustion chamber is 2000 degrees farenheit![addsig]
 
1056644

I would never weld the crack with all the injectors and intake hooked up, I guess I won't be able to get an easy fix with this without tearing the whole thing apart which is not what I fwwl like doing right now. Headers cost between $250-400 and I don't have that kind of play money around now but wish that I did.........Bullet[addsig]
 

1056646

just take off the fuel rail, release the pressure in the lines...[addsig]
 
1056674

If the only crack you have is on top (they usually crack underneath). Clean off everything in the way and have at it with a wire (MIG welder). A window pump sprayer, full of water, keeping the area moist, will reduce heat flexing and really won´t mess with the weld any. It´s actually better to weld the exhaust on the vehicle, as they will flex (from the heat) some and the bolt holes won´t want to align.
Unhooking the computer before welding on the vehicle is recommended.

Early I-6 XJ´s had a recall on the exhaust manifold, the replacement manifold is twice as thick. If you can find a later model at the junk yard, that would really be the way to go. The stock Jeep exhaust manifold on the MPI 4 ltr. is actually a pretty good header.[addsig]
 
1056680

Thanks Chuck, I'll check with Jeeps Unlimited in Providence. When it comes to Jeeps they have everything used and usually very cheap, I've bought alot of things from them. What year XJ manifold can I go up to on my 88.................Bullet[addsig]
 

1056683

Figure all of the stress, money, time, gas, traveling, putties, sealers, and welding to fix a crack that just can't be fixed properly,is expensive in itself.
And if you do some how seal the crack, in time it will crack again.

STOP!

Install a new manifold, or better and cheaper, Stainless Steel smog legal header. You are going to sooner or later, just do it now.

Been there, Done that, replacing it was the way to go. :cool: [addsig]
 
1056687

Note:

Replacing it with a used manifold is also a waste of time and money.
It is already close to cracking due to age and milage.(and it will)
If you don't crack it putting it in.

It takes the same time to install new parts as old, and more time to do it again.[addsig]
 

1056693

Tug didn´t have a bad idea. My first instinct is to head for the old MIG welder. But I´ve seen some brazing and silver solder hold just fine. Soft and flexable often works better.

Morgster does have a point. The I-6 manifoilds, that I have welded did eventually crack again, a couple of years later. Usually right next to where they´d been welded. Also, used headers (exhaust manifolds) have a tendancy, not to fit just right, it is kinda hold your breath and tighten that thing up.

The replacement, manifold is guite a bit thicker and seems to be a milder steel (softer) than the stock manifold. I´ve never seen one of the soft thick ones crack. Once I´d learned the difference, I´d pick through the shelves until I found a good one.

I do know, the last replacement I bought new, was $250 at the dealer.

I first noticed the thick walled headers in 91-92.

If the crack you have, is the only one, try brazing it like TUG mentioned, unless the crack is too big, then you´ll have to weld. When welding, lay a series of spot welds and give the meaterial a chance to cool some, between welds. If it´s not to hard to get too, you can probably get it welded for $20-$30, worth a shot.

I usually have 3-5 cars and trucks around, I only buy new parts when I have to. Keeping those cash cows, in new parts, would keep me broke. :-D [addsig]
 
1056734

I hear ya Morgster but the wallet does not agree right now. My 6 & 8 yr olds birthday party is next week so no extra play money right now :) a friend of mine builds classic cars and has a welder, maybe chucky can help me out on this one. Stay tuned.........Bullet[addsig]
 

1056791

Kids do come first! Mine are 13 and 17 and still haven partys. Now day more me and momma tug than for them. Love them youngens cause soon they will be all grown and gone. Tough when they start talking about milatary and going away to become big people. Jeep stuff will be there when its time. Tug :) / :-( [addsig]
 
1056815

If you promise not to call me Chucky again, I´ll give ya all the help I can. I´ve got one just out on her own, for the first time, requires an occasional infussion of funds, have one starting colledge, and one working as an apprentace pipe fitter. The only way I can keep transportation and my toys on the road, is to cut corners where I can.

If the shop, charges more, than I make an hour, I do it myself, if I have the tools. At least when you get finished, you know what you, got. You get to know the guys at the parts store, develope a relationship, with the guys at the wrecking yard and things get easier.[addsig]
 
1056963

I would never have done this!
If you promise not to call me Chucky again, I´ll give ya all the help I can.
Click to expand...
MudderChuck might start hunting folks down for stuff like that. Funny how it goes in life, you can stick a foot in a mouth and never even taste it till it come back out! hehehehehe tug :-D [addsig]
 

1056995

Just for the record "Chucky" is my friend down the street who builds classic cars not mudderchuck..............Bullet[addsig]
 
1057009

Go to your local welders supply they have special welding rods for cast iron,they are not to cheap but they do work very well, regular welding rods will create carbides next to the weld that will make the cast iron brittle you need to use a rod with high nickle content. :) :) [addsig]
 
1057179

Dude, time for a new exhaust manifold period! Think about a borla header! Super easy to install. What you got, is trash now. Either way, it has to come off, if your gonna try to repair it. Not safe otherwise.

If your not into a header, try a jeep wrecking yard for a new "used" manifold. You can do serious harm to the cylinders near the crack if you let it go!
[addsig]
 

1057465

Ok just got done trying to fix the manifold. I went to Auto Zone and they had a product called ThermoSteel high temp metal repair. It is for manifolds, headers, catalytic conv, boilers, stoves, furnaces, and barbecues. I'll be letting everyone know tomorrow how it worked, if it goes well then it was a great $9 spent................Bullet[addsig]
 
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