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Exhaust leak 1999 s10 blazer...where is it? i dunno, maybe you can help me?

as for being a first time poster, thank you in advance for the help!..just seeing how much money i have to throw at the problem to get another sticker, and stop having to turn my radio up to “ignore it”. little background on me, im 25 and a freshman in college thanks to the gi bill. i live in maine and drive 50 minutes (in good weather) to school and back 4x a week. i need this car to last me the next four years before i can get an upgrade. well, thats enough about me and heres whats going on.

i think i have an exhaust leak in a 1999 s10 blazer lt 4x4 4 door. the loudest spot where i can hear the exhaust noise at cold start and idle, is the passenger side right behind the front tire. on cold mornings where you can see the exhaust smoke prior to warming up i cannot see anything coming from this area. non mechanic types have suggested either the y pipe, or where the y pipe meets the header. but the last thing i want to do is pay a $80-$120 dollar an hour mechanic “just to poke around”. would both have to be replaced to fix this problem if this is the case? and how intensive is this to fix? meaning would the whole motor have to be pulled to remove the entire exhaust piping to have it brazed? my dad is a mechanic, so the tools ive got and his know-how, just need to know what to do so i dont make undue effort and throw my dollar bills in the wrong direction.

also, if anybody has a diffinitive way to tell where an exhaust leak is, beyond having a friend cup their hand over the tail pipe, while they look for it, i would greatly appreciate hearing about it. again, thank you very much for the help and pointing me in the right direction.

Usually, these trucks develop a leak at the flange where the catalytic converter pipe meets the front pipe. Usually, one or more bolts will break and the gasket will blow out. The gasket and three bolts need to be replaced, but this will require an oxyacetylene torch to get the flange hot enough to drive the bolts (knurled studs, actually) out of the front pipe. If you have an exhaust specialty shop do this, it should cost well under $100 in parts and labor and should take a half hour or so to do the actual work.

Correction: the flange is between the catalytic converter and the muffler. Must have been half asleep when I typed that.

The exhaust Y-pipe is sealed to the exhaust manifolds with what are called exhaust doughnuts. These are high temperature gaskets that prevent exhaust gasses from escaping when the pipe is attached to the manifolds. Over time these doughnuts get erroded away from the hot exhaust gasses and start leaking.

Take the vehicle to an independent shop and ask if they can check if the exhaust doughnut is leaking. And if it is, ask how much they’d charge to replace both doughnuts.