Bad motor mounts = cracked header?

[Michaelarchangelo]

I replaced my intake and exhaust manifolds over the weekend and it got me thinking. I have a 98 that didn't have a cracked exhaust manifold until about 4 months ago (177k on motor). Looking at my motor mounts, it seems to me that they need to be changed out, so maybe bad mounts could contribute to extra stress on the exhaust manifold, which then cracks at the collector. Sound like a reasonable idea? Or am I just full of it?

 

[ChiXJeff]

Nope, entirely possible.

Think about it. Bad mounts are going go allow the motor to move around. On mine, I was breaking the exhaust mount over the crossmember.

 

[Vince]

My manifold lasted 13 years before it cracked. When I took it off to replace it I found a broken left hand engine mount.

 

[krelja]

My header has never given me any problems. I've been tring to figure out the standard jeep clunks and during my last trip to paragon I was getting terrible clunks turned out to be a motor mount. Now through the mud on my header I can see a little crack by where the collector is. I bet its because I didn't figure out it was the motor mount earlier