Welding Cracks In A Jeep Manifold

[oldudbob]

A friend of mine dropped the manifold from a 6 cylinder Jeep and cracked it in a couple of places (see attached pictures). He has asked me to weld up the cracks for him. It appears that it is made from steel tubing (not cast iron). I have both a small 100 amp wire welder (no gas) and an 225 Amp Lincoln AC/DC tombstone welder that I can use. Which welder would work best? If I use the stick welder what would be the best rod to use? Any special prep work that needs to be done before welding other than cleaning and grinding?

Any suggestions would be appreciated.

[dandimand]

well i would clean it as well as possible even to the point of sandblasting it. make sure it lines up on head before welding as you dont want it crooked . you could use a mig if that is all you have . use a 75/25 gas and 70s6 wire and go for it. im not sure you skills but its an easy fix . tig would be first choice though .

[Stick rod]

I fixed one of these once and it was stainless.Is this one? Tig would be my first choice,either of your machines should work OK.Double check the type of material.

[1fasbu]

manifold

I fixed one as well, it was ss. If I remember corectly it was dissimilar, in other words half ss/half mild steel. They actually have an updated replacement part for this, it has an expansion joint in it. With the joint it resists cracking during cooling/heating cycles. We bought that one at Lordco, but any parts store should carry it. Oh ya, the new manifold was made in Singapore . Another thing, you can check material with a magnet, chances are that it is 304ss. This will feel only slightly magnetic compared to mild steel. You can weld it with stick if you're good. 5/64 rod of either type. If it's mild steel use the feeder.

[1fasbu]

gasless wire

actually, the gasless wire probably isn't the best choice over stick I've only used the gasless wire once, once was enough. It just requires too much amperage down low to burn.

[JumpinNRollin]

I USE to weld these and they always came back after a couple of weeks cracked in another place. Tell him to get a new manifold (header) and save the time of having to put it on only having to do it again. They are crap metal and have a ton of tube thickness consistancy issues, besides the exhaust pipe going from the exhaust manifold to the back of the Jeep is not supported well, which combined with the sub-standard manifold is just a bunch of vibration which leads to the cracking (especially if he goes through any type of water and it hits the manifold causing quick cooling). The welds always hold but the vibration trnasfer stress to the next weakest area. Sorry for the bad news but I have a bunch of experiance with these things and there is no way around it if he intends on keeping the vehicle. HTH

[JumpinNRollin]

I USE to weld these and they always came back after a couple of weeks cracked in another place. Tell him to get a new manifold (header) and save the time of having to put it on only having to do it again. They are crap metal and have a ton of tube thickness consistancy issues, besides the exhaust pipe going from the exhaust manifold to the back of the Jeep is not supported well, which combined with the sub-standard manifold is just a bunch of vibration which leads to the cracking (especially if he goes through any type of water and it hits the manifold causing quick cooling). The welds always hold but the vibration trnasfer stress to the next weakest area. Sorry for the bad news but I have a bunch of experiance with these things and there is no way around it if he intends on keeping the vehicle. HTH

BTW, if you do try to weld this make sure it is on the engine or clamped to a very flat surface before tacking it. If it is not 100% flat on the flange it will not seal up properly and will constantly burn out the exhaust manifold gasket.

[imported_frank865]

I USE to weld these and they always came back after a couple of weeks cracked in another place. Tell him to get a new manifold (header) and save the time of having to put it on only having to do it again. They are crap metal and have a ton of tube thickness consistancy issues, besides the exhaust pipe going from the exhaust manifold to the back of the Jeep is not supported well, which combined with the sub-standard manifold is just a bunch of vibration which leads to the cracking (especially if he goes through any type of water and it hits the manifold causing quick cooling). The welds always hold but the vibration trnasfer stress to the next weakest area. Sorry for the bad news but I have a bunch of experiance with these things and there is no way around it if he intends on keeping the vehicle. HTH

BTW, if you do try to weld this make sure it is on the engine or clamped to a very flat surface before tacking it. If it is not 100% flat on the flange it will not seal up properly and will constantly burn out the exhaust manifold gasket.

He's right on this...You can weld it, but you can't FIX it. It WILL break somewhere else. The less hassle all around for everyone is to put a new manifold on the Jeep.
Go ahead & weld that one up if you want to....Just don't try to reinstall it. it won't last long if you do.

[Bowtieman31]

As fabsu stated,
This manifold has known problems with cracking. Chrysler is very much aware of the problem and the new replacement manifold has two flexible joints in it. That was Chrysler's answer to the problem.

The new manifold from Chrysler/Jeep runs upwards of $650.00. I don't know if these is an aftermarket source, but I'm sure they don't give them away either.

You will be time and money ahead by just replacing it with a new design.

[oldudbob]

Thanks for all of the input. Based on this input we have decided not to repair this manifold.

[TOMWELDS]

Slap a black jack header on there...L

[precisionworks]

I must be the only one who's welded them without a problem

Maybe it's the filler - Silicon Bronze. Some were as bad as the one you show. The Silicon Bronze is easy to manipulate, as it has a low melt point - it melts WAY before mild steel or SS. Inexpensive, too.

[imported_frank865]

I must be the only one who's welded them without a problem

Maybe it's the filler - Silicon Bronze. Some were as bad as the one you show. The Silicon Bronze is easy to manipulate, as it has a low melt point - it melts WAY before mild steel or SS. Inexpensive, too.

I welded a couple of them..As others stated, the weld was OK it broke beside the weld...When I weld one & reinstall it, when it breaks again...IT'S MY FAULT...& I get to do it again for nothing!!!
I don't weld them anymore.