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Gasket sealer on turbo to cat connection?

1046 Views 6 Replies 5 Participants Last post by  northcountryguy1
My "OEM Grade" MagnaFlow cat broke at one of the welds (cat/pipe joint nearest turbo) after 5 years so I'm replacing it. (BTW, my original cat lasted ~11 years so you be the judge.) Just got the old unit out. Last shop apparently used some copper based gasket sealer on the turbo to cat flange joint. Do I need to use this on the new gasket?

Also, the flange on the downpipe appears to have some remnants of the prior gasket literally welded to the face, see the image below. (Turbo flange is perfectly clean/smooth.) I tried to scrape it off but no success. Is this going to be a problem for making a good seal? Or use the sealent here, too?

Auto part Automotive exhaust
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take something flat, piece of steel or file...and 80 -120 sandpaper and randomly sand it , each time you pass over it you will incur a low spot (minute) but over time these low and high spots will "cancel" each other out and give you a pretty good flat surface, as to using exhaust sealer (brownish tan stuff) don't think it would hurt at that connection aft and not pre cat. ,however properly and sequentially torqued gasket will do it's job, that is why there are only three bolts rather than a greater number.
the other thing is get a good re-enforced gasket with the metal material "rolled over" on inside I.D. of it, no migration of gases eating a path
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