1993 Cadillac Fleetwood Owner's Manual - Page 266

A CAUTION: You can be injured if you try to doservice work on a vehicle without knowing enough about it. 0 Be sure you have sufficient knowledge, experience, and the proper replacement parts andtools before you attempt any vehicle maintenance task. Be sure to use the proper nuts, bolts and otherfasteners. "English" and "metric" fasteners can easily confused. If be you use the wrong fasteners, parts can later break or off. fall You could be hurt. 0 1DOUt FUEL Use regular unleaded gasoline rated at 87 octane or higher. It should meet specifications ASTM D4814 in the U.S. and CGSB 3.5-92 in Canada. Thesefuels should have the proper additives, so you should not have to add anything to thefuel. 1 the U.S. and Canada,it's easy to be sure you get the right kind of gasoline (unleaded). You'll see "UNLEADED" right on thepump. And only unleaded nozzles will fit into your vehicle's filler neck. Be sure the posted octane at least 87. If the octaneis less than 87, you is may get a heavy knockingnoise when you drive. If it'sbad enough,it can damage your engine. If you're usingfuel rated at 87 octane or higher and you stillhear heavy knocking, yourengine needsservice. But don't worryif you hear a little pinging noise when you'reaccelerating or driving up a hill. That's normal,