1968 to 1995 vehicles: the tailpipe test

Before 1996, cars did not carry the standardized OBD II computer that newer cars use for their smog test, so Nevada measures the exhaust itself. The same method covers every heavy-duty vehicle, old or new. If you own a Reno-registered classic that is not on classic plates, a 1990s pickup, or a big gas truck over 8,500 pounds, this is your test.

At a glance

• The two-speed tailpipe method is for 1995 and older vehicles and all heavy-duty vehicles (Nevada DMV).
• Heavy duty means 8,501 pounds and up; light duty is gasoline vehicles up to 8,500 pounds.
• 1967 and older vehicles are exempt.
• A waiver for these vehicles is tied to carbon monoxide or hydrocarbon failures.

Which vehicles get the tailpipe test

The DMV's OBD page puts it in one sentence: vehicles manufactured in 1995 or earlier and all heavy-duty vehicles continue to be tested using the traditional two-speed tailpipe method. In the DMV's vehicle classes, light duty means gasoline vehicles up to 8,500 pounds and heavy duty means 8,501 pounds or more.

So a 1994 sedan, a 1989 pickup and a 2015 gasoline truck with a gross weight rating over 8,500 pounds all take the tailpipe test. A 1996 or newer light-duty car takes the OBD test.

What the test measures

As the name says, the vehicle is tested at two engine speeds, and the analyzer samples the exhaust. The DMV's waiver rules point to what it looks for: carbon monoxide and hydrocarbon levels compared with the standards for the vehicle. High readings mean a fail; the report shows which pollutant was over.

Getting an older car ready

Older engines are more sensitive to the basics. The DMV's general rules apply to them too: gasoline vehicles in Nevada must not emit visible smoke anywhere in the state, and a smoking vehicle cannot get a waiver. A tune-up that is overdue, an oil change long past due or an exhaust leak can all show up in the readings.

Drive the car to the test rather than trailering it in cold, so the engine arrives at normal operating temperature. And test early in your renewal window: an older car is the one most likely to need a repair, and the DMV's 90-day validity gives you room.

When an older car fails

The process is the same as for any vehicle: repair, then pass a retest. If it still fails for carbon monoxide or hydrocarbons after qualifying repairs, it may be eligible for a one-year waiver. In Washoe County that means repairs by a 2G licensed authorized station or the registered owner, with at least $200 in qualifying receipts according to the DMV. See the waiver page.

Classic plates are a separate path

If your older car is registered with Classic Vehicle, Classic Rod or Old Timer plates and driven 5,000 miles or less a year, it may be exempt with the yearly odometer certification. Regular plates mean the regular yearly test. The classic plates page covers the requirements.

Heavy gas trucks and motorhomes

Large gasoline vehicles over 8,500 pounds take the tailpipe test whatever their age. Bay size matters for big vehicles, so call either location before you bring a motorhome or a large truck.