Rusty Or Corroded Apperance on Exhaust Components - keywords corrosion muffler pipe rust

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

GM Engineering has investigated reports of a rusty or corroded appearance of exhaust components on new vehicles being received at the dealer off the transport truck. During certain times of the year, vehicles being produced in Michigan may be exposed to salt used to maintain roads in the winter months. This salt may be present on the plant premises, city streets around the plant or on the transport truck during transit between the plant and the dealer. Some of the exhaust components may have corrosion upon arrival at the dealer as a result of this salt exposure. These exhaust parts are made of a bare mild grade of stainless steel that will oxidize, or look rusty. Over time, these components will have a uniform rusty looking discoloration, which is a normal condition, and these components have been tested to 10+ years in normal service. Additionally, the Vehicle Technical Specifications specify that cosmetic corrosion on these parts, which that are out of the vision of the final customer is acceptable. Customers should be assured that these parts, even though they may have cosmetic corrosion, will not wear out prematurely or result in any type of durability concern.

These components should not be replaced for this surface or cosmetic corrosion.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.