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Exhaust leak

'90 Maxima…A couple of my exhaust studs broke (it was a problem for this model) and now I have an annoying exhaust leak. I tried to put a new gasket, but it started to leak again. I am thinking of using permatex copper sealant…drilling out the broke bolts and replacing them would be very expensive I think. Anybody have experience with this sealant? What are the chances it will work? Thanks.

Where, exactly, are the broken studs located? Are you talking about the studs used to retain the exhaust manifold?

With two adjacent studs broken, sealant is unlikely to stop the leak for long…

If the exhaust manifold studs broke off you have two choices.

Replace the exhaust manifold. Or find someone who’ll weld nuts to the broken off studs to create a way to remove the broken studs. Then replace them with new studs.

Tester

I’m pretty sure you’re talking about the studs in the cylinder head, right? Lots of V-6 Nissans break these studs off, it’s a common problem.

What’s very expensive to you? Check around for a shop with a set of aircraft length drill bits. A shop that’s done these before could probably have those drilled out and retapped for a couple hundred bucks.

Remember that the studs broke because they were under some sort of load. Without replacing them, the remaining studs now have to pick up that load as well as their own.

The chances of the permatex creating a permanent seal are perhaps .00001%.
The chances of the permatex relieveing the now excess load on the other studs is absolute zero.
The chance of the other studs breaking is hard to guess. Perhaps higher than 50%???