My 4 banger was sounding a bit rough, but running fine. I figured the manifold gasket was blown; it was, but so was the manifold!. I've read that Jeep mamnifolds would crack from trail damage issues, but this is clearly not the case here. It looks to me that this thing has been hot, very hot, and has actually began to melt! It could also have been splashed with water when it was hot; that could explain the odd cracking in the center, Or, perhaps that country of origin stamped into it had something to do with it.......
Anyway, I have been wrenching on vehicles for nearly 30 years, and never saw a manifold like this!
NAPA did have one in stock, so the story did have a happy ending!
Was/is the EGR hooked up on that engine? It's weird that it heated so bad in just that area yet the front and rear runners don't look that bad. It is probably a thin cheap cast in the center chamber that overheated. If the EGR is diconnected it will cause hotter EGT's.
89' YJ Larado 4.0L,AX15
05' Grand Cherokee Limited, 2"OME lift and a Hemi.
Everything is hooked up, and I actually just passed emissions testing! Unfortunately, the new one I got came out of the same casting mold as that one did. I was wondering of the "factory" manifolds were also made in China! It would be hard to tell though with the heat shield in place.
My buddy just showed me his manifold off a 1.5L Iron Duke... looks almost the same plus stress cracks all over. Must be from heat, but his just passed CA smog??? Anyone know of a place to find a new/used exhaust manifold for an '80 1.5L Pontiac Iron Duke?
That is CRAZY. I think the cause is just cheap metal from China, maybe with some help from a hot engine and water splashing on it over multiple offroading trips. I used to mess around with drag cars before I started playin with jeeps and those cars mostly had headers - but they get hot as heck and I have seen some manifolds on those cars too. but never saw anything like that. I can't help but thing something was wrong with the metal or how they casted it.