Background

Nevada 1G Inspectors are required to check for visible smoke during the Idle and High-Speed portions of the test. However, not all smoke will cause a vehicle to fail. Smoke can have sources that are unrelated to direct exhaust emissions. For example, an oil leak can drip onto a hot exhaust pipe and give the illusion of crankcase smoke. If you’re not sure if you see smoke, you should stop the test and inspect the exhaust. Smoke will have a burned smell and be opaque. Smoke can be blue or white, depending on the cause. Smoke inspections should only occur once a vehicle has reached operating temperature. If tailpipe or crankcase smoke is visible during the Idle and High-Speed Tests, the vehicle will fail the inspection. Remember, not all visible emissions are smoke! Vapor and moisture from the tailpipe can look like smoke, but are not opaque and have no odor.