How a vehicle built to run on unleaded fuel reacts when diesel is introduced to the mix depends on a number of factors, including how long the vehicle is driven post “infection” and the ratio of unleaded-to-diesel in the system when contamination occurs, as few drivers gas up a truly empty tank, said Jesse Schillinger, owner of Honest Accurate Auto Service on Nevada Mesa View in Colorado Springs. 

Such equations mean the difference between a vehicle that dies on the road and one still able to limp in for a diagnosis, said Schillinger, adding that — as of early Friday afternoon — his shop was handling repairs on two vehicles whose owners suspected they’d fueled up their unleaded vehicles with diesel at affected locations in the Denver area.

“They brought the cars in for rough-running and misfiring. We pulled a spark plug and smelled the fuel and it’s, like, ‘Oh, this is wrong,’” said Schillinger. (For the record, he said the different scent profiles of diesel and gasoline are likely too subtle for a non-mechanic/tech to discern.) 

The Colorado Division of Oil and Public Safety officials have been working with affected consumers while getting the full list of gas stations impacted from the distributor, HF Sinclair. The list includes 48 stations stretching from a Colorado Springs Costco on Barnes Road to a Safeway in Fort Collins.

As with all things in the car maintenance/repair universe, how soon the “Check Engine” light is acknowledged, and the problem addressed, is critical to preserving the life of the vehicle — and the owner’s budget. Getting an unleaded vehicle back up and smoothly running after diesel fuel contamination — which could require removing and flushing the gas tank, inspecting and possibly replacing every component the diesel touched —  isn’t cheap, with costs for customers currently affected by the mix-up running as high $3,500, Schillinger said.

“When you’re at the gas station (and realize you accidentally pumped the wrong fuel)… we can generally drop the tank, empty the fuel, get you back up and going and it’s not that a big a deal,” he said. “Once you’ve run that car and now you’ve got diesel in the system … you’ve affected the fuel pump, you affect the spark plugs …

“It’s a completely different level of damage,” he said.

Schillinger said that in his decades in the business in the Springs, at a company that’s served the community since 1993, this is the first time he’s seen vehicles needing repairs due to fuel mixups that weren’t consumer error, at the pump.

Many commercial gas kiosks offer a range of fuel selections, different categories of unleaded gasoline as well as a blend of ethanol and gasoline (E85), he said. Mistakes can, and do, happen. 

“We’ve seen people do it themselves, (but) I’ve never seen diesel get mixed with unleaded like this at a plant,” he said.

Motorists who filled their vehicles up with gasoline contaminated with diesel last week are scrambling to get them fixed, renting cars, and taking ride shares.

They are also figuring out how to get reimbursed. The mess that began on Jan. 7.

A class-action lawsuit has already been filed.

“You should be able to trust the gas you get at the gas station,” said Sally Smith of Parker. The truck of her husband, Matt, got contaminated. “It’s affected our work, our life — it’s affected everything.”

A request for comment from HF Sinclair by The Gazette was not immediately answered.

More than 600 complaints were received by state officials as of Wednesday.

David Takacs, service manager for Extreme Auto Repair in Parker, said the cars began arriving on Friday and they’ve had a dozen come in since then with issues caused by the contaminated gas.

“They can be sluggish, or won’t even start,” Takacs said. “Sometimes, you’ll see white smoke out of the tailpipe. These engines were not made to run on diesel.”

Class action lawsuit filed

A class-action lawsuit has already been filed by Berger Montague PC, a California-based firm, on behalf of Charlene Franklin and “all others similarly situated.”

It names defendants HF Sinclair Corp. and Dillon Companies LLC doing business as King Soopers Fuel Centers. It alleges negligence, breach of implied warranty of merchantability, breach of implied warranty of fitness for a particular purpose and a violation of Colorado’s Consumer Protection Act.

It states up to 400,000 gallons of fuel may have been affected.

The Denver Gazette’s Dennis Huspeni contributed to this report.