Dear Car Talk:
I accidentally put diesel in my gasoline engine. I drove about 50 miles before bad things began to happen.
Will this destroy my car? — Sarah
No. This is a root canal, Sarah, not an extraction. This can be fixed — with some pain and money.
The reason it took 50 miles to start sputtering and conking out is because you still had a good amount of gasoline in the pump, the fuel line and the fuel rail. Once that pure gasoline was combusted, your engine was trying to combust diesel fuel, which it can’t do.
At this point, the diesel fuel has worked its way through your fuel system and into the cylinders. Not ideal. But I think the patient can be saved.
Your mechanic will have to clean out your entire fuel system. He’ll have to remove and flush out the fuel tank, the pump and the line. He’ll also have to remove the fuel rail — which feeds the injectors — and flush that, too.
There’s undoubtedly some diesel fuel inside the cylinders at this point, too. To get the bulk of that out, he can remove the spark plugs and crank the engine — blowing it out the spark plug holes. And once he gets the fuel injectors spraying pure gasoline again, running the engine should push the rest of the diesel out of the cylinders.
The other possible casualty is your catalytic converter. It’ll probably be OK, but it’s not designed to handle diesel fuel, so time will tell.
The biggest casualty, Sarah (other than your ego)? Your wallet. This is a time consuming, messy job. Removing the fuel rail, in particular, can be difficult on lots of cars. So, expect to spend many hundreds of dollars.
The good news is that the more you spend, the less likely you are to ever do this again. And I’m guessing this’ll be a once-in-a-lifetime experience for you, Sarah. So take pictures.
Got a question about cars? Write to Car Talk write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.
