crack in exhaust manifold -- weld?

[xiphias]

Seem to have a crack in an exhaust manifold. Can this be welded effectively or am I better off replacing the manifold?

 

Thanks for any insight or experiences. It's a 1992 SE 4WD.

[mws]

It can be welded, but the results are unpredictable. If done by a VERY experienced welder, it may be OK. But us amateurs will likely overheat the metal, leading to a very brittle zone around the weld and it will crack again right next to the old crack. If you pull the manifold yourself and have the time to do so, it may be worth it to try. But if you have to pay someone else to do the wrenching, I would advise a new manifold so you only have to pay labor once. And have them change the studs while in there.

 

Many of us have used problems like this as rationalization to get our headers! The stock manifolds are one of the few weak points of the Pathy.

[hmrepairs]

I welded a cracked exhaust manifold on a Dodge work van that I had a couple of years ago. I think, depending on where the crack is, you can expect a good outcome. I'm not real experienced at welding cast, but my grandfather was, so I used some of his pointers. I packed the manifold in sand, (yes you read that right) even inside. The sand is supposed to slow the heating and cooling of the piece during and after welding. Grind the crack evenly, and don't be afraid to penetrate well when welding. And of course a special rod is needed, which I believe is a nickel rod, but I'm not sure about that anymore. When done welding, allow the piece to cool 2-3 hours before removing it from the sand.

 

I'm not sure this is the correct process, but it's how I saw it done growing up, and it worked for me. Good luck

[xiphias]

Thanks for the ideas. Work would be done by the one guy I trust with the truck. He hasn't welded anything for me, but his other work is excellent.

 

Unfortunately, the truck has required a whole bunch of work this year (brakes, clutch, shocks, tires), and right now we're nearly tapped out. Welding is intended to be at the least a stopgap, and potentially longer-term fix. Roaring around town as I am now can't go on much longer.

[dernt]

Replacement manifolds cost about 50 bucks. Why bother welding?