My friend at work has a 2000 Escape with the 3.0L and he has a rather unique problem that I hadn't ever heard of. It has had two EGR valves blow apart at the cast casing. Original thought, some form of a pressure build up, from a clogged exhaust component, or, a form of detonation from too much fuel in the exhaust and an explosion. He took the vehicle to an exhaust shop, and they told him that the 3rd cat had been blown apart and that fragments of it were all the way back into the muffler, so he had that section replaced. He was informed of a leak in the rear manifold, so he has taken to removing those and replacing the studs that have broken, and the gasket to fix the leak. I'm not all together confident that this will fix the underlying issue of why such pressure built in the first place. I would hate to see him go through all this trouble just to have the EGR go into grenade mode again. Any thoughts?
Cheap/poor potmetal EGRs come to mind first. It really depends if it exploded behind or infront of the valve seat, if it's pressure related. However, with a clogged/semi-clogged cat the heat coming into the intake manifold could be enough to touch off the fuel in the intake manifold. So I would also consider a stickey fuel injector in the problem.
Replacing the cat should help or solve the exploding problem.
Ok, we'll hope that takes care of it then. Just such an odd kind of thing, that I was having trouble theorizing how it could have happened. We'll see what happens when he gets it all back together, and I'll post back. Thanks