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obtained on the gauge.
9. Compare the compression reading obtained
for each engine cylinder. The minimum
compression is 12±1
bar.
10. If the compression reading in a cylinder is
below 10 bar, there may be leakage past the
piston rings or valves. Squirt a several drops
of oil into the cylinder bore and perform the
compression test again.
11. If the compression improves after several
drops of oil are squirted into the cylinder
bore, the piston rings are most likely leaking.
If the compression does not improve, the
valves may be allowing leakage.
12. If the compression between two adjacent
cylinders is below the minimum, there may
be a leak in the head gasket between the
cylinders. If suspecting a blown head gasket
check the engine oil and coolant for signs of
contamination. If coolant mixes with the oil in
the sump, the oil will appear to be a dark,
milky, substance. If cylinder compression is
leaking into the coolant, bubbles will appear
in the coolant reservoir while the engine is
running.
II. ENGINE OIL CONSUMPTION TEST
DESCRIPTION
NOTE
Using a weight, grade, or brand of engine
oil other than recommended by TATA
Motors
may
increase
engine
oil
consumption and/or promote engine wear.
Before performing a complete overhaul or major
repair of an engine due to oil loss, first determine
whether the overhaul is necessary. Locate the
cause of the oil loss by searching for external
leaks and internal combustion problems. Check
engine oil consumption to make certain the
amount of oil lost is greater than normal engine
oil consumption.
Determine engine oil consumption by measuring
the weight or volume of oil, driving a
predetermined distance, and then measuring the
oil again. Determining oil loss by means of
visually checking oil level on the dipstick is
inaccurate.
TEST PROCEDURE
1. Park the vehicle on a flat, level surface and
engage the parking brake.
2. Inspect the engine thoroughly for signs of
external leaks through the cylinder head
cover gasket, crankshaft main seals, Crank
sensor, oil sump gasket, oil pump, oil sump
drain plug, etc. Repair any external leaks.
3. If an external leak is not found, fill the engine
oil sump to capacity so the oil level reading
on the sump dipstick is at the 'MAX' mark.
4. Warm the engine so oil temperature is
approximately 75
0
- 80
0
C and then stop and
soak for few minutes.
5. Place a clean suitable container to empty the
engine oil. Use a scale to determine the
weight of the empty container. Record the
tare weight.
6. Completely drain the engine oil into the
container.
7. Replace and tighten the oil sump drain plug.
8. Weigh the engine oil, drained into the pan
(W1).
9. Refill the engine crankcase sump with the
weighed oil. Use care not to spill any oil as
this will make the test inaccurate.
10. Do not use the container for any other
purpose.