I replaced a cracked exhaust manifold (passenger side) a while ago. The second hand replacement is still intact but I didn't fit a gasket cos I was told not to. I've read on the forum that a gasket will reduce the chances of the manifold cracking. Is it worth fitting one at this stage?
if it's not leaking then it's doing it's job so i wouldn't touch it. unfortunately there's no real fix for this, all the manifolds i have seen cracked have been in the same place (the long gap at the back of the lh manifold, to the right of the oil mark on the bottom manifold in the pic) it's a crap design.... if you really want to avoid it happening again then extractors is about it, otherwise it's fit one and hope it lasts...
There was a company manufacturing aftermarket manifolds with a reinforcing web at the point where they crack, selling for about 1/2 the price of the geniune part. That may be worth looking for if there is a recurrence. The use of the gasket allows the manifold to move indendently of the head with thermal expansion, reducing the stress induced in the manifold. I use the gasket but it depends on how much another replacement manifold (and gasket?) costs vs the time taken to fit the gasket now.
