Dear Tom and Ray:
I have two gallons of oil/gas mixture (40-to-1) for my weed whacker that I don’t want to save for next year or try to dispose of. Is it safe to add this mixture to an almost-full tank of gas in my 2004 Honda Accord? I use 87 octane and live in Cleveland. — Jeff
Ray: You live in Cleveland? You may want to just hang on to the gas-oil mixture and buy yourself a snow blower, Jeff.
Tom: Actually, it’s fine to use it in your car. It’s a relatively small amount of oil (1 part oil to 40 parts gasoline).
Ray: It won’t harm the engine, the fuel-injection system or the catalytic converter.
Tom: It’s not great for the environment, but, presumably, you would have burned it in your weed whacker anyway, so it’s doing no more harm being burned by your car.
Ray: Most of my brother’s cars burn more oil than that on their own, due to age and/or disrepair. In fact, some of them burn more oil than gas.
Tom: Keep in mind, you also can save the mixture for next year. Gasoline generally is good for at least a year, these days. You can make it last even longer by adding a small amount of gasoline stabilizer, like Sta-Bil.
Ray: And if you keep it, you also can use it in your lawnmower, your chainsaw, etc.
Tom: But if you do decide to power your Accord with this mix, I would do it over several tankfuls, rather than dumping the whole thing in at once. That’ll minimize the concentration of oil and ensure that no harm is done.