Silicone grease on weatherstrips will make them last longer, seal better, and not stick or squeak. Apply silicone grease with a clean cloth. During very cold, damp weather frequent application may be required.
See Recommended Fluids and Lubricants.
Chevrolet Cobalt Service & Repair Manual. Catalytic Converter R&R
1.
Raise and support vehicle.
2.
Remove wheel drive shaft heat shield.
3.
Remove Heated Oxygen Sensor (HO2S).
4.
Remove catalytic converter to resonator
pipe nuts, Fig. 1.
...