Catalytic converter

OEM Catalytic Converter on a 1996 Dodge Ram B2500 van. Dual inlets, single outlet. old, and about to be replaced.

Law enforcement agencies in Tuolumne County have noted a recent rash of catalytic converter thefts from parked vehicles, including four stolen Monday morning from U.S. Forest Service vehicles at the agency’s Mi-Wok offices off Highway 108 in Mi-Wuk Village. 

The local thefts are part of a surging nationwide trend as rare metals used to make the pollution-control devices have spiked in value, as well as increased demand among thieves that’s partly being blamed on the ongoing COVID-19 pandemic.

Catalytic converters are exhaust emission control devices, intended to reduce toxins and pollutants in exhaust gas from internal combustion engines and convert them into less-toxic pollutants.

Specifically, fuels for internal combustion engines produce toxic by-products like nitrogen oxides, carbon monoxide, and hydrocarbons. Catalytic converters are supposed to reduce those by-products into less hazardous substances, like carbon dioxide, water vapor, and nitrogen gas.

In California, catalytic converters are supposed to be required on all vehicles and be compliant with California Air Resources Board requirements since January 2009.

Platinum, palladium and rhodium are among the valuable metals contained in catalytic converters, which are attached to the undersides of cars, trucks, SUVs, and other vehicles. Scrappers and thieves can collect up to $200 per catalytic converter, according to news reports in Minnesota and other states, and

Car and Driver, an American auto enthusiast magazine and website, reported in late December that two of the three valuable metals found in catalytic converters are now worth more per ounce than gold.

Palladium prices in late December were more than $2,300 per ounce, 20 percent higher than a year ago, according to Car and Driver. Rhodium, which started 2020 around $6,000 an ounce, has increased to more than $17,000 per ounce. Platinum is currently worth more than $1,000 per ounce. Gold is about $1,950 per ounce.

“With national unemployment peaking at a record 14.7 percent in April and lots of high-riding trucks and SUVs left idle or driven less this year, the crime opportunities for catalytic converters this year have been ideal,” Car and Driver reported on Dec. 24.

In Tuolumne County, the most recent catalytic converter thefts have come in bunches over the past two weeks.

The Sheriff’s Office investigated the theft of four catalytic converters Monday morning that were cut off four different U.S. Forest Service vehicles at the agency’s Mi-Wok offices, said Sgt. Robert Nikiforuk, who noted that there were a total of two reported thefts of catalytic converters in November and December.

Four catalytic converter thefts were reported in the City of Sonora over the span of three days from Dec. 20 to Dec. 22.

One was reported at 10:12 a.m. Dec. 20. An East Pasadena Avenue resident said a catalytic converter was removed from a vehicle during the night. The next catalytic converter theft was reported at 1:58 p.m. Dec. 20 from a Fairview Lane resident. Then, at 2:58 p.m. Dec. 21, a woman said a catalytic converter was stolen from her vehicle on Summit Avenue. And at 3:39 p.m. Dec. 22, a catalytic converter was reported stolen off of a vehicle parked on North Norlin Street.

As yet, there have been no suspects identified or arrests made in the recent rash of catalytic converter thefts.

“We can deduce that the increase of catalytic converter thefts is related to the spike in recycle value of some precious metals, in particular platinum, which is at a higher rate now than it's been in several years,” said Sonora Police Chief Turu VanderWiel. “Toyota Prius and Honda Accord seem to be the thieves’ target vehicles of choice and, unfortunately, these thefts can be extremely costly for the victims. We have no evidence to say that these thefts are related, but we are looking into that possibility.”

Vehicle owners should try to park in well-lit areas, in garages or in fenced areas, or in view of surveillance cameras, VanderWiel said. He also urged residents and visitors to report suspicious activity, including individuals loitering near or under parked vehicles.

If your catalytic converter has been stolen, you may not notice it visually because it’s attached to the underside of your vehicle. You will notice when you start the vehicle. Without the catalytic converter, the engine will sound loud and unmuffled, perhaps as loud as a Harley-Davidson motorcycle, according to Edmunds and All State.

When a catalytic converter has been taken off a vehicle, it will make a loud roaring sound that will get louder as you push the gas pedal, according to All State. The vehicle might also make a sputtering, hesitating sound as you change speed. In other words, the vehicle may not drive smoothly.

All State says thieves typically use a saw or wrench or other tools to steal catalytic converters. In some cases, removal of a catalytic converter can take as little as one minute.

Sonora Police Officer Thomas Brickley said Monday his department has had no additional catalytic converter cases reported since Dec. 22.

“We still have no suspects in those cases,” Brickley said in a phone interview. “We're working on identifying any suspects whatsoever. We're investigating the whole thing. We're trying to look into who's doing it, where they’re going, where they're selling.”

Contact Guy McCarthy at or 770-0405. Follow him on Twitter at @GuyMcCarthy.

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