$19.99 for Smog Check for One Car at 4 Less Smog Check ($59.75 Value)

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Up to 67% Off

Customer Reviews

69 Ratings

Very fast, friendly service
Lety M. · October 10, 2016
Quick and friendly service
Jenna H. · October 8, 2016
Excellent customer service!!!
Bre H. · October 6, 2016

What You'll Get


The Deal

  • $19.99 for a smog check for one car ($59.75 value)

Catalytic Converters: Keeping Combustion Clean

Cleaner cars make for cleaner air. Learn how catalytic converters help with Groupon’s guide.

A car’s engine is a dirty place, and it produces even dirtier exhaust. Vapors exit the combustion chamber carrying a nasty trio of smog promoters: nitrogen oxides, hydrocarbons, and carbon monoxide. As these pollutants barrel through the exhaust manifold (the set of tubes that feeds exhaust from each cylinder into the exhaust pipe), there’s only one thing standing between them and the innocent air outside: the three-way catalytic converter.

Situated just before the muffler, the converter is home to honeycombed ceramic cores coated with some combination of platinum, rhodium, and palladium—three rare metals that interact with the main components of the pollutants. When exhaust enters, the metals trigger chemical reactions that heat the gasses and rearrange their molecules. Under their influence, nitrogen oxides splinter into pure oxygen and nitrogen, while hydrocarbons and carbon monoxide are oxidized into less-harmful carbon dioxide and simple water. Since their introduction during the 1975 model year, these unseen cleaners have made air more breathable and much tastier: the EPA estimates that cars built today are 98% cleaner than their counterparts from the 1960s.

The Fine Print


Promotional value expires 120 days after purchase. Amount paid never expires. Limit 3 per person, may buy 1 additional as gift. Does not include $8.25 certification fee per the State of California. Extra $15 fee per vehicle applies for 1999 models and older. Merchant is solely responsible to purchasers for the care and quality of the advertised goods and services.

About 4 Less Smog Check


By purchasing this deal you'll unlock points which can be spent on discounts and rewards. Every 5,000 points can be redeemed for $5 Off your next purchase.