rear exhaust manifold cracked again

[dafeeder]

The rear exhaust manifold on my 96 Chevy Ilumina(3.1) has cracked 3 times in the last 2 years. I think it had a small crack when I bought the car 2 years ago but it has cracked twice since then. I tried real hard to make sure I put the 2nd one on correctly but it still cracked the other day. I am wondering if the material their building the manifolds with is good solid material? The 1st one that cracked should have been the orignal but the last two I got from a national parts store. They gave me the 2nd one free and this one will be also, but it's sort of a pain in the butt to change them every 6 or 8 months. I guess I do have the tilting the motor thing down by now but it's still tough to put on the rear manifold. Do you have any suggestions or comments about this matter?

[dafeeder]

Sorry to reply to my own old thread but the darn manifold just cracked again. This is the 4th time and is really getting old. Has anybody had this issue?

[oldblu65]

Since the original one as well as each replacement have cracked , that should eliminate the idea of a defective part . Most likely it's an issue either with : proper torquing of the part at installation , an unlevel mounting surface ( was all the previous manifold gaskets removed ? ) , or the part is being put into a stress situation ? Are the engine mounts in good condition ? Could the mounts be allowing the engine excessive movement putting the manifold in a bind ? Is the rear manifold in close proximity to hard surfaces where excessive engine movement would cause the two surfaces to hit each other ? More info ?

[dafeeder]

Originally Posted by oldblu65

Since the original one as well as each replacement have cracked , that should eliminate the idea of a defective part . Most likely it's an issue either with : proper torquing of the part at installation , an unlevel mounting surface ( was all the previous manifold gaskets removed ? ) , or the part is being put into a stress situation ? Are the engine mounts in good condition ? Could the mounts be allowing the engine excessive movement putting the manifold in a bind ? Is the rear manifold in close proximity to hard surfaces where excessive engine movement would cause the two surfaces to hit each other ? More info ?

I checked most of that when I went back with the 2nd and 3rd one. I really think the manifolds are being made out cheap materal that won't stand up. The original manifold lasted 12 years.