Dropped $180 on a smoke machine for finding leaks, and it paid for itself in one truck
Bought a smoke machine off the tool truck about 8 months back for $180. Felt stupid walking to my bay with it. The old guys laughed, said I could just use a cigar and my eyes like they did in the 80s. Fast forward two weeks, a 2012 Cummins comes in with a P0299, low boost, no obvious leak anywhere. Pressure tested the charge pipes, held fine. Spent maybe 20 minutes poking around before I remembered the smoke machine in my box. Filled the intake with smoke, and there it was. A hairline crack on the cold side pipe right at a clamp, hidden under grease and grime, invisible to the eye. Customer had already been to two other shops. Nobody found it. I charged him an hour and a half of diag, he was thrilled, and I looked like a genius instead of the new guy. Best part was the guy who called me dumb bought one two months later. What is the one tool you dropped real money on that nobody wanted to give you credit for?