found two small cracks in the stock exhaust manifolds of my 2003 f150 FX4, can they be welded up? i'm just looking for a temporary fix, something to last a year or so until I sell it and get a new truck.

 

I don't see why not. I've never had to,- just migged exhaust myself. Yea, I don't see why couldn't, if you clean it up well.

On the other hand, Dorman sells replacements pretty cheap. I've seen them for as low as $27 on ebay and from Dorman.

Whatever you do, -replace your trans mount. That's why they snap studs @ the manifold. That exhaust damper is bolted to the mount. When the mount wears out, you get allot of vibration thru the Y. This fatigues the manifold bolts. Most likely why yours is cracked.

 

They are cast iron, they can be welded but not very easy to do. You would need to remove them, heat in an oven and weld while still hot. You would need a "high nickel" rod if stick welding, TIG would be a better bet.

I have had some success braising manifolds, but that is a temporary cure at best.

I would get one from a JY or switch to headers.

 

X2 for heads. Welding cast is very difficult, and it won't last.

FYI - I have been welding for quite a few years.