Diesel in Gas Engine: Repair Costs & Alternative Solutions

Diesel in Gas engine

Here’s a firsthand account of someone who had put diesel in a gas engine, what happened, and what the services cost to fix the issue. Word to the wise: don’t zone out while gassing your vehicle; putting diesel in a gas car is an expensive mistake.

Diesel in Gas Engine = Stranded

One day, I received a call from my husband. He was on the side of the road in our three-year old BMW 1-series, waiting for roadside assistance. Out of nowhere, the car had started sputtering, and eventually it slowed from highway speeds down to a crawl, then it stalled and wouldn’t restart.
Cost of Diesel in Gas engine Openbay
The car was still under warranty, so roadside assistance towed it to the BMW dealership.

The Realization

When the service department had some time to look it over, they called us to ask, “Had the car been gassed shortly before this happened?” and the answer was, “Yes.” Sure enough, it was our fault: the technicians detected diesel when they’d found fouled spark plugs, tested some of the fuel. After a couple of days of my husband swearing up and down that the diesel gas pump must have been mislabeled as regular gasoline, he began to admit that it had been a bit of a struggle to get the oddly shaped nozzle into the fuel tank that day. Turns out that if you’re determined enough, you can get that square peg into a round hole and fill your gas car with diesel.

Costly Recommendations

The dealer recommended we get new catalytic converters, which would amount to more than $4,000 worth of labor and parts. We immediately started asking around, and Googling, “What do catalytic converters do?” and why were they so expensive – were these things coated with diamonds or something? Not too far from it – it turns out that catalytic converters use precious metals, including platinum, to chemically convert toxic gasses into cleaner exhaust before it exits your tailpipe.
putting diesel in gas engine is an expensive mistake
Because the cost of replacing the catalytic converters was so high, we initially declined to have them replaced. Instead, we opted to get the car back on the road, hoping the precious catalytic converters would have survived the trauma unscathed. For the first service, we had the diesel fuel drained out, the gas tank cleaned, six spark plugs replaced, fuel pump replaced, five gallons of new fuel added.
Still not cheap, this service would cost us $1854.23. Throw in the nearly $60 worth of diesel they’d drained out, and we’ve now paid $1,913.03. To add insult to injury, when I left the dealer, I had to pay to fill the car with gas, choosing the fuel nozzle carefully, of course!

Sort of Fixed…

Despite the pricey repair, the car wasn’t perfect. When I went to pick up the car at the dealer, the notes indicated we might have issues with the fuel injectors down the line. And, as the service advisor handed me the keys, he said, “It still might give you some issues. … Like the car stalled before I pulled it around here, and you’ll probably have the check-engine light on.” Great.
Dealer repair order for diesel in gas engine
Sure enough, that same day, the check-engine light came on, and it never went off. We just ignored it, figuring it was a small price to pay for an operable vehicle. And we got used to the faint smell of diesel coming from the exhaust.

Back into a Bay

Fast forward six months, when it was time for our annual vehicle inspection, which the car failed. Turns out the emissions were spewing dirty air, and Massachusetts wouldn’t allow its operation. Time to break out the old checkbook for the final fix, and this time, we chose an independent shop.
After an $85 diagnosis, the shop said we probably needed to replace our two catalytic converters. They offered a less expensive alternative first (yes, please!). The suggestion was to see if the issue would go away with new oxygen sensors. The quote was $750, and we accepted. If the new oxygen sensors didn’t pass the emissions test, they promised to install the catalytic converters, minus the labor cost for the sensors. Both services required lots of labor to remove the exhaust system.
Changing out the oxygen sensors didn’t work, so we wound up having them install two new catalytic converters. Even without the labor, they cost $1,798.94. Total spent at the independent shop was $2634. Add that to the initial repairs, and putting diesel in a gas engine wound up costing $4,546.97. Pretty pricey for one tank of gas.

Lesson Learned

All fixed, we drove the car back to the vehicle inspection station and passed.  Finally the nightmare caused by diesel in gas engine had ended!
That was three years ago this month, and it’s since not cost us anything, beyond basic maintenance… until we got the below note on the windshield, from a friendly stranger, and learned the higher price of run-flat tires. But that’s another blog for another time.
Friendly Stranger's Note - Tire Blown

Is this a familiar story? If you’re interested in getting another diagnosis, or want to look for some alternative prices, try Openbay!

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