A low but loud roaring noise or a high-pitched hissing sound while driving can be evidence of an exhaust problem. Leaks in the exhaust pipe/system can be problematic, beyond just the annoying noise, as exhaust leaks also produce a leak of carbon monoxide into the car via the air vents, according to AA1Car.
Cool the engine completely and jack up the vehicle for repair.
Locate the hole and damaged area of the exhaust pipe. Saw off a piece of the pipe with a hacksaw and then level both pieces. There is a possibility that removal of the rubber grommets or support wires, which hold both the muffler and/or exhaust pipe in place, may be necessary.
Make and insert the inner exhaust sleeve: using the tin snips, cut the sheet of aluminium in half. Fold one of the halves in half, creating a double layer of aluminium sheet metal. Wrap the folded half around your broomstick handle, rolling the sheet metal into a sleeve. Roll the sleeve slightly smaller than your exhaust pipe, but not too small, as this will cause it to shift and move around. After creating the inner sleeve, insert it into both parts of the sawn exhaust pipe.
Make and insert the outer exhaust sleeve. With the remaining half of aluminium sheet, fold it in half. Again, use the broomstick handle to roll the piece of sheet metal into a sleeve. This sleeve should be slightly larger than your vehicle's tailpipe. Attach the outer sleeve to the exhaust pipe. The sleeve must overlap both parts of the exhaust that you have sawn and fitted. With the U-bolts, secure the outer sleeve to the exhaust pipe, leaving approximately one-half to one inch of space outside of the U-bolts and enabling you to wrap the pipe with muffler tape.
If your muffler has also failed inspection, experts recommend testing the integrity of the pipes on both sides before replacing. Pipes that appear visually are often faulty.