Start the engine and listen for ticking, puffing, or hissing sounds near the exhaust
Inspect the exhaust manifold, gaskets, pipes, flex pipe, and muffler for visible soot or black residue
Check for rust, cracks, holes, loose bolts, or broken welds in the exhaust system
Feel for escaping air near joints and seams with a gloved hand, keeping clear of hot parts
Use a strip of paper or tissue near suspected leak points to detect movement from escaping gases
Spray soapy water on suspected areas and look for bubbles while the engine is running
Look for exhaust smell inside the cabin or around the engine bay
Check for unusual vibration, reduced performance, or louder-than-normal exhaust noise
Use a smoke machine to pressurize the exhaust and locate escaping smoke
Inspect the catalytic converter, oxygen sensor connections, and flange joints for leaks
Raise the vehicle safely and examine the underside with adequate lighting
Have a mechanic perform a professional exhaust leak test if the source is not obvious