Download ‘03-06 Hummer H2 Exhaust Popping/Snapping Noise When Vehicle – Some clients may comment on a popping/snapping noise from underneath the automobile at idle or instantly after the vehicle is shut off. Some popping/snapping noise from the exhaust system throughout cool down is a traditional condition. The noise may be intermittent depending on the surface temperature and or temperature of the exhaust system on the time of testing.1. Increase and help the vehicle. Check with Lifting and Jacking the Car in Normal Information. Caution: • With a view to keep away from being burned, don’t service the exhaust system whereas it’s still hot. Service the system when it is cool. • At all times put on protecting goggles and gloves when removing exhaust components as falling rust and sharp edges may end in severe personal injury. 2. Remove the nuts securing the muffler to the catalytic converter.