Originally Posted by Kestrel

Until you blow your intercooler up h:

It looks like, since it just split right at the seam, that the weld joint was not done very well. The weld is still attached to both pieces, so bead size I don't think is an issue here, nor is penetration from the bead into the pieces. If I had to venture a guess, I would say that welds were not heat treated. Make sure they heat treat the piece if you have it rewelded. Aluminum welds to about 1/4 strength without heat treatment, and gets to about 1/2 strength with heat treating.