1993 Buick LeSabre Owner's Manual - Page 233

Fuel Use regular unleaded gasoline rated at 87 octane or higher. It should meet specificationsASTM D48 14 in the U.S. and CGSB 3.5-92 in Canada. These fuels so should have the proper additives, you should not have to add anything to the fuel. In the U.S. and Canada, it's easy to be sureyou get the right kind of gasoline (unleaded). You'll see "UNLEADED' right on the pump.And only unleaded nozzles will fit intoyour vehicle's filler neck. Be sure the posted octane is at least 87. If the octane is less than 87, you may get aheavy knocking noise when you drive. If it's bad enough, it can damage your engine. If you're using fuel rated at 87 octane or higher and you still hear heavy knocking, your engine needs service. But don't worry if you hear a little pinging noise when you're accelerating or driving a hill. That's normal, up and you don't have tobuy a higher octane fuel to get rid of pinging. It's the heavy, constant knock that means you have a problem. What about gasoline with blending materials that contain oxygen, suchas MTBE or alcohol? MTBE is "methyl tertiary-butyl ether." Fuel that is no more than 15% MTBE is fine for your vehicle. Ethanol is ethyl or grain alcohol. Properly-blended fuel that is no more than 10% ethanol is fine for your vehicle. Methanol is methyl or wood alcohol. Fuel that i more than 5% methanol is bad for s your vehicle. Don't use it.It can corrodeI.., parts in your fuel system and also damage plastic and rubber parts. That damage wouldn't be covered under your warranty. And even 5 at or less, there mustbe "cosolvents" and avoid corrosion preventers in this fuel to help these problems. Gasolines for CleanerAir Your use of gasoline with detergent additiveswill help prevent deposits from formingin your engine and fuel system. That helps keep your enginein tune and your emission control system working properly. It's good for your vehicle, and you'll be doing your part for cleaner air. Many gasolines are now blended with materials called oxygenates. General Motors recommends you use that 231