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lou's garage

My friend is freaking out, she just put 1/4 tank of diesel in her minivan (a Grand Caravan). She only drove it a short bit. Her mechanic and dad said because it was only one-quarter of a tank, she can fill it with regular gas but the dash light might come on and it might smoke a bit. She followed the advice from the mechanic and now her van won’t start. Help! – Danielle

I have received multiple phone calls from panic-stricken customers standing at a pump, not sure what to do after having just put diesel into a gasoline powered car.

Diesel cannot be combusted in a gasoline engine so being stranded is imminent when significant quantities are involved.

If more than one litre is involved, stop and get the vehicle towed to your service provider immediately. Do not start the car.

If we receive the car before it has been started and ran, we will simply drain the fuel tank thoroughly and fill with the correct fuel and send you on your way. When we have to deal with a situation like your friend’s, we still drain the tank and refill, but we also have to get the remainder of the errant fuel out of the complete fuel system. This can be relatively simple, to a downright nightmare depending on the vehicle.

I have twice had owners of high-end European vehicles initiate an insurance claim because the cost was going to be significant.

I was considering purchasing a 2007 or 2008 Lexus IS250 AWD. My question for you is, can I use regular gasoline or do I have to use the premium? – Daniella

Can I use regular fuel in a 2016 Mercedes E 400? Jim

I have answered this before, but given that this question lands regularly, I will add some additional thoughts.

Your vehicle’s knock sensors will detect the grade of fuel being used and adjust ignition timing and fuel injection parameters according to the fuel being used. After long-term use, the onboard powertrain control module (PCM) will adjust and limit performance characteristics.

I doubt the vehicles in question will suffer a noticeable driveability loss when using regular. However, your vehicle manufacturer spends a great amount of time and effort designing a product that burns fuel as effectively and as cleanly as possible. Circumventing that design will likely not damage the engine under normal driving conditions, but there is risk when extreme loads and heat are the norm.

There are drivers that use regular in place of premium and swear they are saving a small fortune in fuel. Results are going to vary from car to car. Premium is a must for performance-orientated, turbocharged vehicles. I am of the opinion, that if you are going to buy a vehicle that requires premium fuel, you should expect to have to live with the additional fuel costs, otherwise choose another vehicle.

Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail, placing “Lou’s Garage” in the subject line.

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