1998 Lexus LS400 lexus LS400 1998 Engine / LEXUS 1998 LS400 OWNER'S MANUAL (OM50498U)

ENGINE
226 COOLING SYSTEM
Capacity
Coolant type
10.8 L (11.4 qt., 10.4 lmp.qt.)
Ethylene glycol coolant (Do not use alcohol type.)
FUEL
Fuel type
Octane rating
Only UNLEADED
91 (Research octane number 96) or higher
IGNITION SYSTEM
Spark plug Make DENSO
NGK
Gap
SK20R11
IFR6A11
1.1 mm (0.043 in.)
ELECTRICAL SYSTEM
Battery Maintenance type battery
Specific gravity reading at 20C (68F):
Charging rates Quick charge
Slow charge
Nonmaintenance battery
Open voltage at 20C (68F):
Charging rates
1.260 Fully charged
1.160 Half charged
1.060 Discharged
15A max.
5A max.
12.7V Fully charged
12.3V Half charged
11.9V Discharged
[Voltage that is checked 20 minutes after the key is removed with
all the lights turned off]
5A max.

ENGINE
227
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.
At a minimum, the gasoline you use should meet the specifications
of ASTM D4814 in the U.S.A. and CGSB 3.5M93 in Canada.
NOTICE
Do not use leaded gasoline. Use of leaded gasoline will cause the
threeway catalytic converter to lose its effectiveness and the
emission control system to function improperly. Also, this can
increase maintenance costs.
Octane rating
Select premium unleaded gasoline with an Octane Rating of 91
(Research Octane Number 96) or higher for optimum engine
performance. However, if such premium type cannot be
obtained, you may temporarily use unleaded gasoline with an
Octane Rating as low as 87 (Research Octane Number 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 buildup of engine deposits.
For further details, ask your Lexus dealer or a local gasoline retailer.

ENGINE
228
Improved gasolines
The American Automobile Manufacturers Association (AAMA)
has developed a specification of improved gasolines. The AAMA
specification offers optimal fuel information for better vehicle
performance and better protection of your engine.
Lexus recommends the use of gasolines that meet the AAMA
specification, if available, for improved drivability and emission
control system.
Gasolines containing MTBE
Gasolines that contain MTBE (Methyl TertiaryButyl 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 stop using them.
Gasolines containing MMT
Some gasolines contain an octaneenhancing additive called
MMT (methylcyclopentadienyl manganese tricarbonyl).
Lexus does not recommend the use of gasolines that contain MMT.
If fuels containing MMT are used, your emission control system may
be adversely affected. The Malfunction Indicator Lamp on the
instrument cluster may come on. If this happens, contact your Lexus
dealer for service.
Gasolines containing alcohol
Gasohol is a mixture of gasoline and ethanol. If you use gasohol
in your Lexus, be sure that it is unleaded, has an octane rating
no lower than 87 and does not contain more than 10% ethanol.
Lexus does not recommend the use of gasolines containing
methanol.
If you use gasoline containing methanol, use only gasoline meeting
the requirements above and also containing less than 5% methanol
with cosolvents and corrosion inhibitors for methanol.
NOTICE
Do not use gasohol other than stated above. It will cause fuel
system damage or vehicle performance problems.
If drivability problems are encountered (poor hot starting,
vaporizing, engine knock, etc.), discontinue its use.
Take care not to spill gasohol during refueling. Gasohol may
cause paint damage.
Fuel tank capacity
85 L (22.5 gal., 18.7 lmp.gal.)

ENGINE
229
FACTS ABOUT ENGINE OIL
CONSUMPTION
Functions of engine oil
Engine oil has the primary function of lubricating and cooling the
inside of the engine, and plays a major role in maintaining the engine
in proper working order.
Engine oil consumption
It is normal that an engine should consume some engine oil
during normal engine operation. The causes of oil consumption
in a normal engine are as follows.
Oil is used to lubricate pistons, piston rings and cylinders. A thin
film of oil is left on the cylinder wall when a piston moves
downwards in the cylinder. High negative pressure generated
when the vehicle is decelerating sucks some of this oil into the
combustion chamber. This oil as well as some part of the oil film
left on the cylinder wall is burned by the high temperature
combustion gases during the combustion process.
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 by highspeed driving 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

ENGINE
230Failure to check the oil level regularly could lead to serious
engine trouble due to insufficient oil.
For detailed information on oil level check, see ”Checking the
engine oil level” on page 230.
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.
CHECKING THE ENGINE OIL
LEVEL
62L004-4
With the engine at operating temperature and turned off, check
the oil level on the dipstick.
1. To get a true reading, the vehicle should be on a level spot. After
turning off the engine, wait a few minutes for the oil to drain back
into the bottom of the engine.
2. Pull out the dipstick, and wipe it clean with a rag.
3. Reinsert the dipstick and push it in as far as it will go, or the
reading will not be correct.

ENGINE
231
62L002-1
1
Add oil 2
O.K. 3
Too full
4. Pull the dipstick out and look at the oil level on the end. If it is
between the full line (
5
) and the low line ( 4
), it is O.K.
62L003-3
If the oil level is below or only slightly above the low line, add
engine oil of the same type as already in the engine.Remove the oil filler cap and add engine oil a little at a time, checking
the dipstick. The approximate quantity of oil needed to fill between
the low line and the full line on the dipstick is indicated below for
reference.
When the level reaches within the correct range, return the filler cap
and turn the cap clockwise until you hear a click.
Oil quantity. L (qt., lmp. qt.) 1.5 (1.6, 1.3)
NOTICE
Avoid overfilling, or the engine could be damaged. Check the oil
level on the dipstick once again after adding the oil.

ENGINE
232
Engine oil selection
Use API SH, ”EnergyConserving II” or SJ, ”EnergyConserving”
multigrade engine oil or ILSAC multigrade engine oil.
Recommended viscosity (SAE):
62L0051
Temperature range anticipated before next oil change
SAE 5W30 is the best choice for your vehicle, for good fuel
economy, and good starting in cold weather.
If you use SAE 10W30 engine oil in extremely low
temperatures, the engine may become difficult to start, so SAE
5W30 engine oil is recommended.
Oil identification marks
62L0061
API Service Symbol
ILSAC Certification Mark
Either or both API registered marks are added to some oil containers
to help you select the oil you should use.
The API Service Symbol is located anywhere on the outside of the
container.
The top portion of the label shows the oil quality by API
(American Petroleum Institute) designation such as SJ. The
center portion of the label shows the SAE viscosity grade such as
SAE 5W30. ”EnergyConserving”, shown in the lower portion,
indicates that the oil has fuelsaving capabilities.
The ILSAC (International Lubricant Standardization and
Approval Committee) Certification Mark is displayed on the
front of the container.

ENGINE
233
CHECKING THE ENGINE
COOLANT LEVEL
62L007-2
1
Reservoir cap 2
Upper line 3
Lower line
Park the vehicle at a level spot and look at the seethrough
coolant reservoir when the engine is cool. The coolant level is
satisfactory if it is between the upper and lower lines on the tank.
If the level is low, add ethyleneglycol type coolant.
The coolant level in the reservoir will vary with engine coolant
temperature. However, if the level is on or below the lower line, add
coolant to bring the level up to the upper line.
Use only ethyleneglycol type coolant. It will prevent freezing and
corrosion. Neither supplemental inhibitors nor additives are needed
nor recommended. (For information on ethyleneglycol coolant,
see also ”Engine coolant selection” described below.)If the coolant level drops within a short time after replenishing, there
may be a leak in the system. Visually check the radiator, hoses,
reservoir cap, drain cock and water pump.
If you can find no leak, have your Lexus dealer test the cap pressure
and check for leaks in the cooling system.
CAUTION
To prevent burning yourself, do not remove the reservoir cap
when the engine is hot.
Engine coolant selection
Your coolant must contain ethyleneglycol antifreeze. In addition
to preventing freezing and subsequent damage to the engine, this
will also prevent corrosion. Further supplemental inhibitors or
additives are neither needed nor recommended.
Read the antifreeze container for information on freeze protection.
Follow the manufacturer’s directions for how much to mix with
water. The total capacity of the cooling system is given on page 226.
We recommend 50% solution be used for your Lexus, or a sufficient
quantity to provide protection to about 35C (31F).
NOTICE
Do not use alcohol type antifreeze or plain water alone.