7-7
Chapter 7
WEEKLY CHECKS
Every internal combustion engine uses a certain amount of oil, especially when
running-in. The engine is dependant on oil for lubricating the cylinder walls, pistons,
rings and valve stems. A thin lm of oil is left on the cylinder walls, some of which is
carried into the combustion chamber and burnt during the combustion process. This
also applies to the lm of oil on the valve stems which is drawn into the combustion
chamber and burnt.
There are several other factors that contribute to the rate of oil consumption in your
engine: worn pistons, rings, valve stems and guides; the way in which the vehicle is
operated; the quality and grade of oil; the oil level, and dilution of the oil.
Operation of the vehicle
High speed driving and heavy towing increases engine temperature, which lowers oil
viscosity, causing more oil to reach the combustion chamber and get burnt away.
Quality and grade of oil
Oil viscosity is a signicant factor in oil consumption. If you use an oil which is too thin
(low viscosity) your oil consumption will increase. Use only the recommended grades
of oil. Refer to Specications in chapter 8.
Oil level
Maintaining a proper oil level is also an important factor in controlling oil consumption.
An over full engine will splash oil onto the cylinder walls in quantities greater than the
piston rings can control. This excess oil will be drawn into the combustion chamber and
burnt, or may result in aeration of oil in the sump causing damage to the engine.
Dilution
Probably the most prevalent complaint of oil consumption comes from the driver whose
vehicle is frequently driven at below normal operating temperatures. The oil becomes
diluted by fuel and moisture which settles in the oil pan and may even raise the oil
level creating a false reading on the oil level dipstick. For example, in a vehicle that
has accumulated 1,500 km of short distance or intermittent city operation and has
consumed a normal amount of oil, the level may not have dropped from the full mark,
due to dilution. If this vehicle is driven for some distance at highway speeds on a warm
day, the dilution elements evaporate, lowering the oil level and the motorist assumes
the oil lost has been consumed in the highway operation.
If, after taking into account the above factors, you are still concerned that your engine
has excessive oil consumption then you should discuss the situation with a Holden
Dealer. Remember that an engine’s oil consumption should not be judged until it has
run at least 10,000 km.
ENGINE OIL CONSUMPTION
CAPTIVA BOOK.indb 7 30/05/2007 12:49:59 PM
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