1996 Chevrolet Astro Owner's Manual - Page 211

In the United States and Canada, it's easy to be sure you 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 at least 9 1 forpremium, 89 formiddle grade is and 87 for regular. If the octane is less than 87, you may get aheavy knocking noise when you drive. If it's bad enough, itcan damage your engine. If you're using fuel rated at 91 octane orhigher 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 to buy a higher octane fuel to get of it. It's the heavy, rid constant knock that means you have a problem. What about gasolinewith blending materials that contain oxygen (oxygenates), such as 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 orgrain alcohol. Properly-blended fuel that is no more than 10% ethanol is fine foryour vehicle. Methanol is methyl or wood alcohol. NOTICE: Fuel thatis more than 5% methanol is badfor your vehicle. Don't use it. It can corrode metal parts in your fuel system and also damage plastic and rubber parts. That damage wouldn't be covered under your warranty. And even5% or less, there at must be "cosolvents" and corrosion preventers in this fuel to help avoid these problems. Gasolines for Cleaner Air Your use of gasoline with deposit control additives will help prevent deposits fromforming in your engine and fuel system.That helps keep your engine in tuneand your emission controlsystem working properly. It's good for your vehicle, and you'll be doing your part for cleaner air. Many gasolines arenow blended with oxygenates. General Motors recommends that you use gasolines with these blending materials, such as MTBE and ethanol. By doing so, you can help clean the air, especially in those partsof the countrythat have high carbon monoxide levels. In addition, some gasoline suppliers are producing reformulated now gasolines. These gasolines are specially designed to reduce vehicle emissions. General Motors recommends that you use reformulated gasoline. 6-3