Has anyone else had problems with exhaust leaks where the donut gaskets are? It has been fixed by a mechanic once, by me once, and I can hear it happening again (over about 5 years). Anyone with a fix that will last longer?

 

BK94si, I've had the same problem on my "99"(189 K). We had to grind the nubs on the cast iron flange so it will tighten better. Then after we did that the pipe cracked around the flange (fatigued Pipe). That was fixed at a muffler shop by making a new flange and doubling the flange on the pipe(one inside the other ) Ihaven't had any problems since.
Good Luck, Dondobe

 

I just replaced the pass side donut on my 99 K2500 454 Suburban and the new one was considered "second design", it was white and thicker. I hope it lasts....

 

I,ve also had good look with the thick white donuts. I'll keep you updated if they go again