Fuel - Use of 15 Percent MTBE
89cadillac15NO.: 90-I-11
DATE: 6C
GROUP: 930108
CORP. NO.: Oct. 1989
SUBJECT: USE OF 15 PERCENT MTBE IN FUELS
In August of 1988, the U.S. Environmental Protection Agency approved the use of methyltertiary-butyl ether (MTBE) in gasolines at concentrations of 15 percent or less. Prior to that time, the legal limit was 11 percent. Cadillac Owner's Manuals stated that the use of gasolines containing 11 percent or less MTBE should not adversely affect the operation of the vehicle and would be covered by the New Vehicle and Emission Control Systems warranties. The use of 15 percent MTBE in gasoline should also not adversely affect the operation of 1990 and earlier model vehicles; and therefore, will not void any warranties covering those vehicles. In the interest of contributing to cleaner air, Cadillac recommends that all model year vehicles use such fuels whenever available. The 1990 and future Owner's Manuals will reflect this position.
MTBE is not alcohol. Cadillac maintains its stance on alcohol-fuel blends:
As stated in Cadillac Owner's Manuals, properly blended fuel containing concentrations of no more than 10% ethanol is fine for Cadillac vehicles. More than this amount may deteriorate the rubber components in a vehicle's fuel system and void the vehicle's warranty.
Methanol can be safely used in fuel concentrations no more than 5%. Use of fuel with higher concentrations may corrode metal parts, deteriorate rubber components in a vehicle's fuel system, and will void the vehicle's warranty.