SAFARI

4 DLT ENGINE

gasket. To ascertain the point of leakage, spray

small quantity of clean engine oil in to cylinder

showing low pressure. If it improves, wear in piston

rings / cylinder bore is indicated. If it does not,

leakage past the valves is indicated. If

compression pressure of adjacent cylinder is also

on lower side 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 separator 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

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/120 miles

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 :

Standard oil consumption

(W1-W2) (Wt. of oil consumed gms.)X1000

C (Litres / 1000km)

sp. gvt. of oil (gm)XD (drive dist. in km.)

C =

(W1-W2)

litres/1000km

0.88 x D

If the oil consumption value is more than 0.8 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

decelerations for comparatively long time, then the

oil consumption may show variation over the specified

values.

3. EXTREMELY LOW OIL PRESSURE

Check the following :

xternal leakages.

il level in sump upto maximum mark on dipstick.

il pressure indicator for proper functioning.

unctioning of pressure relief valve on oil pump.

il pump performance.

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.

4. MECHANICAL FAILURES

Defective water pump or alternator can be a source

of mechanical noise. Defect can be located by

replacing alternator, water pump with NEW one.

Metallic knocking sound from an engine may be due

to faulty injection, excessive clearance in main and

big end bearings, small end bush, tappets, piston slap,

seizing of piston rings, scored cylinder bore or

breakage of any moving parts. Noise due to defective

fuel injection equipment is generally termed as

‘DIESEL KNOCK’ and can be eliminated by attending

to fuel injection equipment. By cutting off high pressure

line to individual injectors with engine running will pin

point the cylinder with Diesel Knock. Overhauling of

fuel system will set right Diesel Knock.

Dismantling of engine may be considered if still noise

occur even after attending all above mentioned

problems.

Noise can be from turbocharger unit. For details refer

the trouble shooting chart in turbocharger section.