Understanding the Catalytic Converter

The last two months I have explained some of the newest technologies that are coming out on the newest models. This month we will look at a technology that almost every car out there already has; the catalytic converter.

The catalytic converter has been around for a long time. It was first mandated by Federal law in 1975. Modern catalytic converters are used to eliminate three important pollutants from exhaust - carbon monoxide, nitrogen oxides, and hydrocarbons. These pollutants react with air and sunlight to form smog, especially in the summer. They also cause ground level ozone, contribute to acid rain and the depletion of the ozone layer in the upper atmosphere. I tell you all this so that you can see how you help to minimize air pollution in Atlanta by properly maintaining your vehicle and its catalytic converter.

Of course, another precious resource that many people are very concerned with is preserving the "greenbacks" in their wallets. Properly maintaining your car prolongs the life of your catalytic converter. A catalytic converter is expensive to replace because of the precious metals that it is made from. The three primary metals that enable a catalytic converter to remove pollutants are platinum, rhodium, and palladium. Platinum costs $1600 an ounce, and rhodium costs $7000 an ounce. If you thought your catalytic converter was "gold plated", you were grossly underestimating it!

Under ideal conditions your vehicle's catalytic converter should never fail. In practical application we see many cars with 200,000 miles where the original factory catalytic converter is still working perfectly well. Catalytic converters fail for only three reasons - mechanical damage, chemical contamination, or over temperature.

Mechanical damage is usually the result of running over something in the road. It does not cause an immediate failure, but begins the breakdown of the internal components. Chemical contamination is usually the result of a small fluid leak into the combustion chamber in the engine, usually motor oil or antifreeze. Over temperature failures are the result of too much fuel because of worn or damaged oxygen sensors. The most common cause of catalytic converter failure is someone driving a vehicle for several weeks or months with the Check Engine light or Service Engine Soon light illuminated.

Federal law requires manufacturers to provide an eight year, 80,000 mile warranty on the original catalytic converter. The warranty may not apply if one of the above mentioned conditions can be shown to have caused the catalytic converter to fail. Failure of the catalytic converter at less than 80,000 miles is pretty rare, and manufacturers are usually very generous in overlooking contributing factors that were under the drivers control.

When replacing a catalytic converter outside of warranty there are basically two choices. You can replace it with an original equipment part, or with a "universal fit" after market catalytic converter. The universal fit converter is often half the price of an original equipment converter. Remembering the cost of the precious metals used, how do you think the manufacturer of the universal fit converter saves money?

We have found through hard-learned lessons that the effectiveness and longevity of the universal fit catalytic converter is often much less than the original equipment catalytic converter. We have never had a failure on a replacement original equipment converter. We have had too many universal fit converters cause the Check Engine light to come back on after a week, a month, or a year. We now only use original equipment converters, if they are still available for a particular vehicle.

Brian Klaubert has written for the Neighborhood News for five years, and owns Christian Brothers Automotive – Hamilton Mill on Braselton Hwy in Dacula. They have won “Best Mechanic” in the 2007 “Best of Gwinnett” award in Gwinnett Magazine.