maintenance lexus LS400 1994 Engine / 1994 LS400: ENGINE

ENGINE
195
FUEL
Fuel type
Your vehicle must use only unleaded gasoline.
To help prevent gas station mixups, your Lexus has a smaller
fuel tank opening. The special nozzle on pumps with unleaded
fuel will fit it, but the larger nozzle on pumps with leaded gas
will not.
NOTICE:
Do not use leaded gasoline. Use of leaded gasoline will
cause the three-way catalytic converter to lose its
effectiveness and the emission control system to
function improperly. Also, this can increase
maintenance costs.
Octane number
Select premium unleaded gasoline with a Research
Octane Number of 96 (Octane Rating 91) or higher for
optimum engine performance. However, if such premium
type cannot be obtained, you may temporarily use
unleaded gasoline with an octane number as low as 91.
Use of unleaded fuel with an octane number or rating lower
than stated above will cause persistent heavy knocking. If
severe, this will lead to engine damage.If your engine knocks ...
If you detect heavy knocking even when using the
recommended fuel, or if you hear steady knocking while
holding a steady speed on level roads, consult your Lexus
dealer.
However, now and then, you may notice light knocking for a
short time while accelerating or driving up hills. This is no
cause for concern.
Gasolines containing detergent additives
Lexus recommends use of gasolines that contain
detergent additives to avoid build-up of engine deposits.
For further details, ask your Lexus dealer or a local gasoline
retailer.
Gasolines containing MTBE
Gasolines that contain MTBE (Methyl Tertiary-Butyl Ether)
are available in the market. If you use a gasoline mixed
with MTBE, make certain that it does not contain more
than 15% of MTBE.
If the use of gasolines containing MTBE causes poor drivability
and / or poor fuel economy, you should discontinue the use of
fuels containing MTBE.

ENGINE
197 Oil is also used to lubricate the stems of the intake valves.
Some of this oil is sucked into the combustion chamber
together with the intake air and is burned along with the fuel.
High temperature exhaust gases also burn the oil used to
lubricate the exhaust valve stems.
The amount of engine oil consumed depends on the
viscosity of the oil, the quality of the oil and the way the
vehicle is driven.
More oil is consumed under driving conditions such as high
speeds and frequent acceleration and deceleration.
A new engine consumes more oil, since its pistons, piston rings
and cylinder walls have not become conditioned.
When judging the amount of oil consumption, keep in
mind that the oil may have become diluted, making it
difficult to judge the true level accurately.
For example, if a vehicle is used for repeated short trips and
consumes a normal amount of oil, the dipstick may not show
any drop in the oil level at all, even after 1000 km (600 miles)
or more. This is because the oil is gradually becoming diluted
with fuel or moisture, making it appear that the oil level has not
changed.
The diluting ingredients evaporate out when the vehicle is then
driven at high speeds, as on an expressway, making it appear
that oil is excessively consumed after driving at high speeds.
Importance of engine oil level check
One of the most important points in proper vehicle
maintenance is to keep the engine oil at the optimum level so
that oil function will not be impaired. Therefore, it is essential
that the oil level be checked regularly. Lexus recommends that
the oil level be checked every time you refuel the vehicle.
NOTICE:
Failure to check the oil level regularly could lead to
serious engine troubles due to insufficient oil.
For detailed information on oil level check, see “Checking the
engine oil level” on page 198.
USED ENGINE OIL
CAUTION:
Used engine oil contains potentially harmful
contaminants which may cause skin disorders such as
inflammation or skin cancer, so care should be taken to
avoid prolonged and repeated contact with it. To
remove used engine oil from your skin, wash
thoroughly with soap and water.
Do not leave used oil within the reach of children.
Dispose of used oil and used oil filters only in a safe and
acceptable manner. Do not dispose of used oil and
used oil filters in household trash, in sewers or onto the
ground. Call your Lexus dealer or a service station for
information concerning recycling or disposal.