1993 GMC Safari Owner's Manual - Page 243

Ifyou'reusing fuel ratedat 91 octaneorhigherandyoustillhearheavy if youhearalittle knocking,yourengineneedsservice.Butdon'tworry pinging noise whenyou'reaccelerating or driving upahill.That'snormal,and youdon'thavetobuyahigheroctanefueltogetrid of pinging.It'sthe heavy,constantknockthatmeansyouhaveaproblem. Whataboutgasolinewithblendingmaterialsthatcontainoxygen,suchas MTBEor alcohol? MTBE is "methyltertiary-butylether."Fuelthat fine for your vehicle. is nomorethan 15% MTBEis Ethanol is ethyl or grainalcohol.Properly-blendedfuelthat 10% ethanol isfineforyourvehicle. Methanol is methyl orwood alcohol. is nomorethan it. Fuel that is more than 5% methanol is bad for yourvehicle.Don'tuse It can corrode metal parts in your fuel systemandalsodamageplastic and rubber parts. That damage wouldn't be coveredunderyourwarranty. Andeven at 5% or less, there must be "cosolvents" and corrosion preventers in this fuel to help avoid theseproblems. Gasolines for Cleaner Air Your use of gasoline with detergent additives will help prevent deposits from forming in yourengineand fuel system.Thathelpskeepyourengine in tune andyouremissioncontrolsystemworkingproperly.It'sgoodforyourvehicle, air. and you'll be doing your part for cleaner Manygasolines are nowblendedwithmaterials called oxygenates.General Motorsrecommendsthatyouusegasolineswiththeseblendingmaterials, so, youcanhelpcleantheair, suchasMTBEandethanol.Bydoing especially in those parts of thecountrythathave high carbonmonoxide levels. In addition,somegasolinesuppliersarenowproducingreformulated gasolines.Thesegasolinesarespeciallydesigned to reducevehicle emissions.GeneralMotorsrecommendsthatyouusereformulatedgasoline. in thoseparts of the By doing so, youcanhelpcleantheair,especially countrythathavehighozonelevels. if theirgasolinescontain You shouldaskyourservicestationoperators if theyhavebeenreformulated to reduce detergentsandoxygenates,and vehicle emissions. 6-5