GENERAL INFORMATION AND MAINTENANCE 1-51
Recommended viscosity (SAE):<: 5W-30 Preferred
v> | K
IOW-30 >; -Z9 -18 -7 4 16 2-r 38
F -20 0 20 40 60 60 100
Temperature range anticipated before next oil
changeFig. 144 Oil viscosity chart—2TZ-FZEAP; :
ft. ,'"4 ."If" A ADON'T POLLUTE. RESOURCES,
Fig. 145 Look for the API oii identification label when choosing
your engine oilfore be slightly heavier than and not as ideal in cold weather as the 10W-
40, but would offer better protection at higher rpm and temperatures
because when warm it acts like a 50 weight oil. Whichever oil viscosity you
choose when changing the oii, make sure you are anticipating the tempera-
tures your engine will be operating in until the oil is changed again. Refer
to the oil viscosity chart for oil recommendations according to temperature.
The API (American Petroleum Institute) designation indicates the classi-
fication of engine oil used under certain given operating conditions. Only
oils designated for use "Service SH" (or its superseding type) should be
used. Oils of the SH type perform a variety of functions inside the engine in
addition to the basic function as a lubricant. Through a balanced system of
metallic detergents and polymeric dispersants, the oil prevents the forma-
tion of high and low temperature deposits and also keeps sludge and parti-
cles of dirt in suspension. Acids, particularly sulfuric acid, as well as other
by-products of combustion, are neutralized. Both the SAE grade number
and the APE designation can be found on top of the oil can.
Diesel engines also require SH engine oil. In addition, the oil must qual-
ify for a CO rating. The API has a number of different diesel engine ratings,
including CB, CC, and CD. Any of these other oils are fine as long as the
designation CC appears on the can along with them. Do not use oil labeled
only SH or only CC. Both designations must always appear together.
For recommended oil viscosity's, refer to the chart. Note that 10W-30
and 10W-40 grade oils are not recommended for sustained high speed dri-
ving when the temperature rises above the indicated limit.Synthetic OilThere are many excellent synthetic and fuel-efficient oils currently avail-
able that can provide better gas mileage, longer service life, and in some
cases better engine protection. These benefits do not come without a few
hitches, however, the main one being the price of synthetic oils, which is
three or four times the price per quart of conventional oil.
Synthetic oil is not for every car and every type of driving, so you should
consider your engine's condition and your type of driving. Also, check your
car's warranty conditions regarding the use of synthetic oils.
Both brand new engines and older, high mileage engines are the wrong
candidates for synthetic oil. The synthetic oils are so slippery that they can
prevent the proper break-in of new engines; most manufacturer's recom-
mend that you wait until the engine is properly broken in 5,000 miles
(8,046km) before using synthetic oil.
Consider your type of driving. If most of your accumulated mileage is
high speed, highway type driving, the more expensive synthetic oils may be
of benefit. Extended highway driving gives the engine a chance to warm up,
accumulating less acids in the oil and putting less stress on the engine
over the long run. Under these conditions, the oil change interval can be
extended (as long as your oil filter can last the extended life of the oil) up to
the advertised mileage claims of the synthetics. Cars with synthetic oils
may show increased fuel economy in highway driving, due to less internal
friction. However, many automotive experts agree that 50,000 miles
(80,465km) is too long to keep any oil in your engine.
Cars used under harder circumstances, such as stop-and-go, city type
driving, short trips, or extended idling, should be serviced more frequently.
For the engines in these cars, the much greater cost of synthetic or fuel-
efficient oils may not be worth the investment. Internal wear increases much
quicker on these cars, causing greater oil consumption and leakage.FUELIt is important to use fuel of the proper octane rating in your car. Octane
rating is based on the quantity of anti-knock compounds added to the fuel
and it determines the speed at which the gas will burn. The lower the
octane rating, the faster it burns. The higher the octane, the slower the fuel
will burn and a greater percentage of compounds in the fuel prevent spark
ping (knock), detonation and preignition (dieseling).
As the temperature of the engine increases, the air/fuel mixture exhibits a
tendency to ignite before the spark plug is fired. If fuel of an octane rating
too low for the engine is used, this will allow combustion to occur before
the piston has completed its compression stroke, thereby creating a very
high pressure very rapidly.
Fuel of the proper octane rating, for the compression ratio and ignition
timing of your car, will slow the combustion process sufficiently to allow
the spark plug enough time to ignite the mixture completely and smoothly.
Many non-catalyst models are designed to run on regular fuel. The use of
some super-premium fuel is no substitution for a properly tuned and main-
tained engine. Chances are that if your engine exhibits any signs of spark
ping, detonation or pre-ignition when using regular fuel, the ignition timing
should be checked against specifications or the cylinder head should be
removed for decarbonizing.
Vehicles equipped with catalytic converters must use UNLEADED GASO-
LINE ONLY. Use of unleaded fuel shortened the life of spark plugs, exhaust
systems and EGR valves and can damage the catalytic converter. Most con-
verter equipped models are designed to operate using unleaded gasoline
with a minimum rating of 87 octane. Use of unleaded gas with octane rat-
ings lower than 87 can cause persistent spark knock which could lead to
engine damage.
Light spark knock may be noticed when accelerating or driving up hills.
The slight knocking may be considered normal (with 87 octane) because
the maximum fuel economy is obtained under condition of occasional light
spark knock. Gasoline with an octane rating higher than 87 may be used,
but Toyota recommends a 91 octane rating for proper operation.