A Calgary Co-Op store will be footing the bill for repairs after a fuel mix-up led to about 500 drivers filling their cars with diesel fuel instead of regular gas over the holidays.

The mix-up occurred at the Co-Op gas station on MacLeod Trail S. at 88 Ave.

One Calgary driver says that after he filled up at the station, he knew something wasn’t right.

“The car started fine,” says Colin Pratt. “The battery was fine, but it wouldn’t stay running and I had to keep trying to rev it up to keep it going.”

Pratt and his wife were getting ready for a road trip to Vancouver on December 27 and filled his Volvo at the station on Boxing Day, the same day that a supplier filled a regular storage tank with diesel fuel.

Co-Op was made aware of the issue 26 hours later and has since been using membership numbers to find drivers affected by the problem.

Pratt is a Co-Op member and says that the company left him a voice mail to explain the mix up.

He says they told him to take it in to a shop and get the system flushed. “They would be covering all expenses. They gave me the information about the insurance company and contacts if we required a rental car. They were great as far as I was concerned.”

They got the news about the gas issue when they returned from Vancouver and say, aside from the engine light being on the whole time and trouble getting their vehicle going, they managed the trip just fine.

Karen Allan, spokesperson for Co-Op, says that they understand that the issue has been a huge inconvenience for their customers. "We are trying to make the process as easy as possible for them."

Allan says the company has been covering the costs for repairs and services due to the contaminated fuel and providing car rentals and paying for towing services for people who've been stranded.

She says that they were initially alerted to the issue by one of their members. "They had some issues with their car and they took it to a repair shop who identified that problem. They phoned us right away and as soon as we were even suspicious that there was diesel in our tank, we shut down services immediately."

Allan says that the issue was pure human error and they are working with their supplier to ensure this problem never happens again.

At the station, she says they had to pump all of the contaminated fuel out of the tank and flush the lines before filling it with regular gas again. "I just gassed up there on Sunday and I've had no issues with my car."

She says that Co-Op apologizes for any inconvenience they may have caused as a result of the issue and they are working to track down all the people who used the service station who aren't members.

Customers who believe they may have used the Macleod Trail gas station on Dec. 26 or 27 can call Co-Op's head office and they will be walked through the claims process.

Putting diesel fuel into a gasoline engine can cause a host of problems including the engine simply not running at all.

Nathan Bracko, the assistant shop foreman at Valentine Volvo, says that the car will generally stall out and the driver will be stranded. "They'll need a tow to a service station."

He says once the car gets there, they'll need to push the vehicle into the service bay and drain the tank as much as they can. "We'll fill the tank with gasoline and and pump as much fuel through the system as we can. Once we feel we've removed most of the diesel, we'll run it and try and burn off any of the remain diesel."

Bracko says that the whole process will take about two to three hours, depending on the volume of diesel in the tank and how long it takes to get the fuel system flushed out.

Diesel fuel has a tendency to clog fuel lines, filters, and injectors.

If the engine does run, it will provide very poor performance while driving, as in the Pratts’ situation. This is because the cylinders of the gas engine don’t provide enough heat or pressure to properly ignite the diesel fuel.

"Diesel is designed to work at a different temperature range, so the diesel engine is designed to run at different specifications that gasoline isn't," Bracko says.

In extreme situations, it may be necessary to replace parts of the fuel system and engine pistons.

The cost to flush diesel fuel from a car is anywhere from $500 to a few thousand dollars.

Bracko says that typically diesel fuel pumps are clearly marked and even have different nozzles that don't fit into a regular gas tank.

But, in a situation like Pratt's, it is difficult to tell the difference. "If you're not familiar with the smell, you probably wouldn't notice," Bracko says.

He adds that it is a totally different story if regular gas is used in a diesel engine - drivers could be needing to pay to repair serious engine damage if they attempt to do that.