300Tdi Discovery
V8i
1
FAULT DIAGNOSIS
ENGINE OIL PRESSURE TEST
Service tools:
LRT-12-052: Pressure test equipment
WARNING: Use suitable exhaust
extraction equipment, if test is being
carried out in workshop.
WARNING: If vehicle has been running,
engine oil will be hot, care must be taken
when fitting equipment to prevent
personal injury due to scalding.
Test
1. Check lubricant is to correct level.
2. Place vehicle on a ramp [hoist].
3. Disconnect battery negative lead. Remove oil
pressure switch.
4. Fit the test gauge.
5. Reconnect battery negative lead.
6. Start and run engine to normal operating
temperature.
7. At a steady engine speed of 2500 rev/min -
engine oil pressure reading should be - 2.75 bar
(40 lbf/in
2
).
8. If the pressure is low - Remove and overhaul oil
pump
CYLINDER COMPRESSION - TEST
Equipment:
Compression pressure gauge
Test
1. Start and run engine until normal engine
operating temperature is achieved (thermostat
open).
2. Remove all spark plugs.
3. Disconnect both coil negative (WB) leads
4. Insert compression gauge, crank engine until
reading stabilises.
5. Expected readings, throttle fully open, battery
fully charged:
8.31:1 = 10.2-10.9 bar, 150-160lbf/in
2
9.35:1 = 11.5-12.2 bar, 170-180lbf/in
2
