Chevrolet 1993 Astro Passenger Owner's Manual page 242

Fuels in Foreign Countries
If you plan on driving in another country outside the
U.S.
or Canada,
unleaded fuel may be hard to find. Do not' use leaded gasoline. If you use
even one tank full, your emission controls won't work well or at all. With
continuous use, spark plugs can get fouled, the exhaust system can corrode,
and your engine oil can deteriorate quickly. Your vehicle's oxygen sensor will
be damaged. All of that means costly repairs that wouldn't be covered by
your warranty.
To check on fuel availability, ask an auto club, or contact a major oil
company that does business in the country where you'll be driving.
You can also write us at the following address for advice. Just tell us where
you're going and give your Vehicle Identification Number (VIN).
General Motors of Canada, Limited
International Export Sales
P.O. Box 828
Oshawa, Ontario L1H 7N1, Canada
Filling Your Tank
PO389
6-6