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ENGINE
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and equal, it may be due to blown cylinder head
gasket.
2. EXCESSIVE ENGINE OIL CONSUMPTION
High engine oil consumption may also lead to
overhauling of the engine but before proceeding to
overhauling, check following points :
1.
Make sure that there is absolutely zero external
leakage of the oil (i. e. from the camshaft oil seal,
crankshaft oilseal, oil sump gasket, oil pump
gasket, cylinder head cover gasket etc.
2.
Ensure that oil seperator condition is OK & no
leakage in the circuit.
3.
If no external leakage is found, determine the
exact engine oil consumption, as per following
procedure.
Determining exact engine oil consumption :
Caution :
Do not make a rough estimate of engine oil
consumption by noting the kilometers covered by
the vehicle at any random stage and finding oil
consumed from the topped up position taking into
consideration dipstick level and oil tank capacity.
Procedure :
1.
Once it is doubted that engine oil consumption
is higher, place the vehicle on level ground.
2.
Top up oil sump to its capacity as recommended.
3.
Warm up the engine so that oil temperature is
75-80
0
C.
4.
Now take a clean vessel, place it below the drain
plug of oil tank.
5.
Drain the hot oil into the clean vessel. Drain it
fully.
6.
Screw in oil sump drain plug and tighten it.
7.
Weigh the vessel along with oil let this weight
be ‘w1’ gms.
8.
Refill the weighed oil into the oil tank. Do not
spill any oil. The vessel used for draining should
not be used for any other purposes.
9.
Load the vehicle approximately to rated GVW.
Drive vehicle for at least 200 km under normal
operating conditions. Let this drive distance be ‘D’
kms.
10. Immediately after the test drive, place the vehicle
at the same spot from where it started.
11. Now place the same previously used vessel below
the oil tank, unscrew the drain plug and drain off
oil into the vessel drain the tank fully.
12. Weigh the vessel along with oil, now for the
second time. Let this weight be ‘W2’ gms.
13. Find out standard oil consumption as :
(W1-W2)
(Wt.ofoil consumed gms) X1000
(W1-W2)
‘C’ = litres/1000km
0.88 x D
If the oil consumption value is more than
0.4 Ltr./1000 kms. then engine needs further
investigation.
Note :
The oil consumption of engine depends on
the oil conditions (e. g. viscosity, cleanliness and
grade of oil etc.) and the driving conditions. If the
vehicle is driven in high speeds, as may be the case
on highways, and /or with frequent accelerations
and declerations for comparitively long time, then
the oil consumption may show variation over the
specified values.
3. EXTREMELY LOW OIL PRESSURE
Check the following :
a.
E
xternal leakages.
b.
O
il level in sump upto maximum mark on dipstick.
c.
O
il pressure indicator for proper functioning.
d.
F
unctioning of pressure relief valve on oil pump.
e.
O
il pump performance.
f.
C
logged oil filter
If oil pressure is found to be less than 2.8 bar at
maximum speed and 1.2 bar at idling speed, it may
be due to improper functioning of oil pump or defect
in oil pump relief valve.
If low oil pressure is not on account of above factors,
wear of journals / bearings is indicated for which
overhaul of engine may be considered.
sp. wt. of oil (gm)X‘D’ (drive dist. in km.)
Standard oil
consumption
‘C’(Litres/1000km)
=