Okay, so I have had an exhaust leak for a little while now on my 69/350ci. It is where my passenger side exhaust manifold meets the turndown tube for my exhaust. The first time I noticed it, the three bolts to hold them together were loose. I have since tightened them to the Nth degree. Yet the leak is still there. Is there something to wrap around this spot, or some sealant for exhausts (wow that sounds dumb)...anyway, anything I can do, or tips for fixing it.

Thanks
Tim

you could go to a muffler shop, buy a piece of replacement exhaust section with both ends slightly enlarged, so you can just slip it over your existing exhaust, and then grind off the section you need, lube the ends up with silicone, or normal bearing grease and clamp it in, or weld it, its up to you really. Thats what i would do. By the way, what the grease does, is it when the exhaust gets hot, the grease becomes a powder sort of material, and coats the inside of the exhaust to leave a nice smooth inside of the exhaust. Good luck on that :)

I'm having the same type of problem, bolts getting loose. I got an exhaust gasket from autozone and put in there. Its basically a metal gaskets with paper on both sides and three holes that slip over the studs from the exhaust header. This did the trick for a while however, Its starting to leak again. I have not gotten under there yet to see if the bolts are loose again or if the gasket gave. I'm hoping they are loose, although I used lock tight on them the last time.

It is possible the prior leak burned a slight hole or notch in the exhaust "doughnut" that seals the system. Before you run out and get one, see if you can feel the escaping exhaust on your hand and determine exactly what size doughnut you need. 2", 2 1/4", 2 1/2 ".

New gaskets or donuts (stock exhaust) and lock washers should fix a leak and keep the bolts from coming loose in the future. The problem typically is the bolts come loose causing an exhaust leak that damages the gasket or donut. Just tightening the nuts doesn't help for long if the gasket is damaged...

Pass side, w/manifolds? Heat riser valve? Is it there? is it either functional or welded open? Is the gasket above it good? Pretty sure the pass side manifold does not have the rounded inside edge to accept the doughnut, that's on the bottom of the heat riser valve.

Thats correct! On the pass side its not set for the donuts. In my case I have the spacer without the heat riser door in it. I know the gasket above it is good, I just keep having trouble at the other end were it connects to the rest of the pipe.

If you have a heat riser spacer with the flapper removed it will eventualy develope an exhaust leak at the shaft. Sometimes the manifold to headpipe extension (what the donut goes around) will rust out and then it will leak.

Its actually a heat riser spacer made without the flapper, so there are no holes. Ricks sells one, its part # RC-154.

Yeah, I have seen those. I just check the nuts on the exhaust flange everytime I change the oil. Sometimes they are loose and sometimes not. I have brass nuts on the maniforld after twisting one of the steel ones off when changing the gasket between the manifold and the heat riser.

The RH exhaust manifold outlet surface is flat, so the top of the heat riser valve (also flat) will seal to the manifold with the metal-reinforced flat gasket. The bottom of the heat riser valve is chamfered, to accept the (angled) surface of the "donut" seal, and the top of the exhaust pipe flange is also angled to match the lower surface of the donut seal, and it also requires the stepped insert extension to support the I.D. of the donut so it doesn't disintegrate and cause an exhaust leak. The top of the exhaust pipe will NOT seal to the face of the exhaust manifold flange, no matter what you do - you either need the heat riser valve in place, or a spacer with the top surface flat and the bottom surface chamfered in order to make up a correctly-sealing joint. :thumbsup:

and it also requires the stepped insert extension to support the I.D. of the donut so it doesn't disintegrate and cause an exhaust leak.

I think John may have hit it here... is that lil piece of pipe in there?

Another thing I'm remembering from another post is a replacement pass side exhaust pipe that was not bent at the correct angle... Does your pipe meet square with the heat riser?

Actually, Jim I think you hit on my problem. I had a muffler shop re-adjust my exhaust as they were rubbing on the rear axle. They cut my pipes at a point in the midle of the car and shorten them by an inch or so to properly position them over the axle. Whoever installed the system the first time didn't line things up properly.

I have a felling when they did this, that my connection at the exhaust manifold was loose, so now it does not line up to well there.

If everything is lined up and square with the manifold it should never come loose. Your front exhaust pipe is supposed to have a sleeve on the top of it for the gasket to slide over. If that sleeve isnt there it will eventually blow out the donut. If it isnt lined up or doesnt have the sleeve any half decent exhaust shop can cut your front pipe and rebend you one that is square with the sleeve pretty cheap.