COASTER_AE
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FUNCTIONS OF ENGINE OIL
Engine oil has t he pri mary f unctions of
lubri cati ng and cooli ng the ins ide of the
engine, and plays a major rol e in main-
taini ng t he engi ne in proper wor king order.
ENGINE OIL CONSUMPTION
It is normal that an engine should con-
sume some engi ne oi l dur ing normal
engine operat ion. The causes of oil
consumption in a normal engi ne are as
follows.
D Oil is used to l ubric ate pistons , piston
rings and cy linder s. A thin fil m of oil
is l eft on the c ylinder wall when a pi s-
ton moves downwar ds in the cy linder.
High negativ e pres sure generat ed when
the vehi cle is deceler ating suck s s ome
of this oil into the c ombustion chamber.
This oi l as well as some part of the oi l
fil m left on the cyli nder wall is burned
by the high t emperatur e c ombustion
gases duri ng the combust ion proces s.
D Oil is also us ed to lubricat e the st ems
of t he int ake valv es. Some of this oil
is suck ed i nto t he combusti on c hamber
together with t he int ake air and i s
burned al ong with the fuel. High tem-
peratur e exhaus t gases als o burn the
oil used t o l ubric ate t he ex haust valve
stems.
A certain amount of engi ne oil wi ll be
consumed while driving. In the follow-
ing si tuati ons, oi l consumpt ion may in-
crease, and engine oil may need to be
refilled in between oil maintenance in-
terval s.
D When t he engine i s new, for example
direc tly after pur chas ing the vehicle or
after r eplaci ng the engine
D If low quality oil or oil of an inappropri-
ate vis cosi ty is us ed
D When driv ing at high engine s peeds or
with a heav y load, when towing or
when driv ing w hile ac celerat ing or de-
celer ating fr equently
D When leav ing the engine i dling for a
long time, or when driv ing frequentl y
through heavy traffic
IMPORTANCE OF ENGINE OIL LEVEL
CHECK
One of the most i mportant point s in prop-
er vehic le m aintenanc e is t o k eep the en-
gine oil at the optimum level so that oil
funct ion wil l not be im paired. Therefor e, it
is essent ial that the oil l evel be check ed
regular ly. Toyota recommends that the oil
level be checked every time you refuel
the vehic le.
NOTICE
Failur e t o check the oil level regul arly
could lead t o serious engine trouble
due to insufficient oil.
For det ailed infor mation on oil lev el check ,
see “Chec king the engine oil lev el” in Sec-
tion 7−2.
Finish
Facts about engine oil
consumption
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