2019 Subaru forester, four days old, wife noticed dark rust around the end of the muffler where piece of pipe is welded on. this is supposed to be a new SUV. why

  • 1
    Welcome to Motor Vehicle Maintenance & Repair! Take it back to the dealership and tell them to fix it. There is something called an "adjustment period". Most vehicle manufacturers cover this sort of stuff for one year from purchase of your vehicle. You don't like something, take it back and tell them to fix it. It won't cost you a thing. Jun 2 '19 at 20:18

A fairly common cause of "rust" on stainless is contamination with carbon steel ; such as a steel brush used the prepare or clean the stainless weld, also cleaning the stainless with steel/cast iron shot as a Wheelabrator. And normal high temperature oxides on the stainless from production or welding ; with time these usually black oxides become brownish as routine rust. These are only cosmetic conditions . Modern exhaust systems are 13% chrome ( ferritic ) stainless.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.