Can I sue a mechanic that doesn’t have a business license for damages to my car? Would it be worth it financially?

Location: WA state

I’m honestly not sure if he has a license, but he destroyed my engine by getting contaminants into the combustion chamber and claiming it was 100% removed out. I have this in text. Upon starting the car, which he’d left after he finished his job, the engine broke down and caused irreparable damage.