I was replacing the gasket between my exhaust manifold and down pipe tonight, got everything back as I think it should be and I feel what I percieve to be an exhaust leak on the engine side of the pipe.

Should I have used some sealant on the gasket? I bought the gasket and the nuts from the dealership.

Also, how tight should I tighten the nuts? I just cranked them down.

Thanks for any and all insight.

That gasket doesn't require sealant. The important thing is to tighten the 3 nuts evenly, so that the gasket seats and crushes properly. Use anti-sieze on the studs. I don't use a torque wrench, but I have found that tightening those nuts as much as possible by hand with a 6-inch ratchet is enough.

Also: if your previous gasket was leaking for any significant amount of time, it is possible that the leaking exhaust has etched a piece of the manifold or the pipe, and the mating surfaces may no longer be flat. If this is the case, you will need to have this issue fixed or else no gasket or any amount of sealant will ever work.

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Matt L. -- Cary, NC -- '89 740 sedan -- '91 740 wagon

thanks for the information. Besides "feel", is there a good way to test for leaks throughout the system?

I like the "in the ear" approach.

Find yourself a 3-foot piece of CLEAN fuel hose. Stick one end in your ear (if it's greasy hose, you'll have a grubby ear). Use the other end as a sorta cheap mechanic's stethoscope and probe around under the exhaust manifold and behind the flange until you loudly and clearly hear the leak.
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Don Foster (near Cape Cod, MA)

Put a rag in the tailpipe (not tight enough to stall the engine) and then the exhaust leaks are easier to find. Obviously you don't want to put an oily or gasoline-soaked rag in there, and don't use a nice one. Or you can have a friend partially block it with something while you look for the leaks.