For years now I've been aware of an exhaust leak at the exhaust manifold/down pipe fitting. There is a gasket that fits here and I was pretty sure mine was shot. Periodic tightening of the bolts helped a bit, but not much.
My hand was forced the other day when I went out to the Jeep and noticed the tail pipe touching the ground. I'd been hearing a rattling sound from beneath/behind me while driving for a few days and upon inspection found that one of the pipe hangers had come loose from the bottom of the tub. This, in turn, led to the tail pipe completely separating from the muffler—and noise.
So, I figured here was the perfect opportunity to replace that gasket!
Off to the local Napa Auto Parts I went. They didn't have the gasket in stock, but had it for me within about three hours.
Below on the left is the old gasket. Completely shot and falling apart. Also note that the gasket is only rounded on one side. The other just has straight sides. The straight sided half is what fits into the exhaust manifold. The rounded side fits within the flare of the down pipe.
On the right, the replacement with Napa part number. It's a FelPro gasket and I've read that they don't last as long as an all-steel donut, but it's what they had. Part number 60299.
On my Jeep the mechanism that holds the exhaust down pipe to the manifold is a sort of butterfly clamp. Really, just two u-bolts with holes on each end which slip over the studs fitted into the manifold. Tightening these simply forces the pipe firmly to the manifold. However, this relies on the end of the pipe being flared a bit. Wouldn't work with a straight pipe. I've seen some pipes with much of the flare broken off. That would probably require replacement of the pipe. Fortunately mine is intact.
Below, left, you can see the u-bolts opened on one side. Rather than the retaining nut on that side coming off, the entire stud unscrewed from the manifold. Fair enough, won't complain. On the other side things were much more difficult and I didn't want to risk shearing off the stud. So I just backed the nut off as much as I could and swung the u-bolts clear.
On the right is the down pipe itself. Note the flare at the end. (And pay no attention to the trashed heat-riser tubing that leads up to the air cleaner—I thought it would be cooler to have the flex tube in black rather than silver. All that black cracked and came off within months. Waste of money, I'll buy the cheaper silver next time…)
After a bit of bad language I managed to get the gasket in place while also forcing the down pipe up while having to navigate past the two u-bolts and the nut/stud holding them on. Tip for others: loosen the entire exhaust system at the hangers to allow some fore and aft play as you get things bolted together. Once the manifold is buttoned up you can snug up the rest again.
Entire project: about $8 and two hours of time beneath the Jeep (mostly climbing back out to get things I'd forgot umpteen times).