Cadillac CTS Owner's Manual page 324

$10araCTS Page 324 Tuesday, September 15, 2009 12:30 PM
Service and Maintenance
The use of gasoline with an
octane rating lower than that
recommended may cause engine
knock. Continued use can cause
engine damage and void the
warranty.
If you detect a heavy engine knock
even when using a gasoline of the
recommended octane rating, have
the engine checked. Short periods
of engine knock during hill climb-
ing and acceleration are accept-
able.
To help keep fuel injectors and
intake valves clean, see your dealer
for information about preventing
deposit-related problems.
. . . 324
FUEL ADDITIVES
Gasoline should contain detergent
additives that will help prevent
engine and fuel system deposits
from forming. Clean fuel injectors
and intake valves will allow your
emission control system to work
properly. Some gasoline does not
contain sufficient quantities of
additive to keep fuel injectors and
intake valves clean. To make up
for this lack of detergency, it is
recommended that GM Fuel
System Treatment PLUS (GM part
no. 88861011) be added to the
fuel tank at every oil change or
every 15000 km, whichever occurs
first.
Gasoline containing oxygenates,
such as ethers and ethanol,
may be available in your area.
However, fuels containing more
than 10% ethanol, such as E-85
(85% ethanol), or more than
15% MTBE (an ether) should not
be used in vehicles that were not
designed for those fuels.