1A3-10 GENERAL ENGINE INFORMATION
OIL LEAK DIAGNOSIS
Most fluid oil leaks are easily located and repaired by
visually finding the leak and replacing or repairing the
necessary parts. On some occasions a fluid leak may
be difficult to locate or repair. The following
procedures may help you in locating and repairing
most leaks.
Finding the Leak
1. Identify the fluid. Determine whether it is engine
oil, automatic transmission fluid, power steering
fluid, etc.
2. Identify where the fluid is leaking from.
2.1 After running the vehicle at normal operating
temperature, park the vehicle over a large
sheet of paper.
2.2 Wait a few minutes.
2.3 You should be able to find the approximate
location of the leak by the drippings on the
paper.
3. Visually check around the suspected component.
Check around all the gasket mating surfaces for
leaks. A mirror is useful for finding leaks in areas
that are hard to reach.
4. If the leak still cannot be found, it may be
necessary to clean the suspected area with a
degreaser, steam or spray solvent.
4.1 Clean the area well.
4.2 Dry the area.
4.3 Operate the vehicle for several miles at
normal operating temperature and varying
speeds.
4.4 After operating the vehicle, visually check the
suspected component.
4.5 If you still cannot locate the leak, try using the
powder or black light and dye method.
Powder Method
1. Clean the suspected area.
2. Apply an aerosol-type powder (such as foot
powder) to the suspected area.
3. Operate the vehicle under normal operating
conditions.
4. Visually inspect the suspected component. You
should be able to trace the leak path over the white
powder surface to the source.
Black Light and Dye Method
A dye and light kit is available for finding leaks, Refer
to the manufacturer's directions when using the kit.1. Pour the specified amount of dye into the engine
oil fill tube.
2. Operate the vehicle normal operating conditions
as directed in the kit.
3. Direct the light toward the suspected area. The
dyed fluid will appear as a yellow path leading to
the source.
Repairing the Leak
Once the origin of the leak has been pinpointed and
traced back to its source, the cause of the leak must
be determined n order for it to be repaired properly. If
a gasket is replaced, but the sealing flange is bent,
the new gasket will not repair the leak. The bent flange
must be repaired also. Before attempting to repair a
leak, check for the following conditions and correct
them as they may cause a leak.
Gaskets
lThe fluid level/pressure is too high.
lThe crankcase ventilation system is malfunctioning.
lThe fasteners are tightened improperly or the
threads are dirty or damaged.
lThe flanges or the sealing surface is warped.
lThere are scratches, burrs or other damage to the
sealing surface.
lThe gasket is damaged or worn.
lThere is cracking or porosity of the component.
lAn improper seal was used (where applicable).
Seals
lThe fluid level/pressure is too high.
lThe crankcase ventilation system is malfunctioning.
lThe seal bore is damaged (scratched, burred or
nicked).
lThe seal is damaged or worn.
lImproper installation is evident.
lThere are cracks in the components.
lThe shaft surface is scratched, nicked or damaged.
lA loose or worn bearing is causing excess seal
wear.
DIAGNOSIS
GENERAL ENGINE INFORMATION 1A3-11
28bar
Approx.18bar
Max. 3bar
COMPRESSION PRESSURE TEST
1 Test Adapter
2 Flexible Connector
3 Compression Pressure Recorder
Tools Required
000 589 65 09 00 Socket
001 589 73 21 00 Hand Vacuum Pump
Service Data
Normal Compression Pressure
Minimum Compression Pressure
Permissible Pressure Difference Between Individual Cylinders
lEngine at normal operating temperature of 80°C
1A3-12 GENERAL ENGINE INFORMATION
Compression Pressure Measurement
Notice
Ensure that no gear is engaged and that the vehicle is
protected from rolling.
1. Run the engine to be the coolant temperature 80°C.
2. Remove the fuel injection nozzle.
Socket Wrench Insert 001 589 65 09 00
3. Install the test adapter (1) and connect the flexible
connector (2) to the compression pressure recorder.
Compression Pressure Recorder 001 589 76 21 00
4. Disconnect the vacuum line from the stop unit and
connect the hand vacuum pump to the stop unit.
5. Pump the hand vacuum pump and make the fuel injection
pump in stop position.
Operating PressureApprox. 500bar
Hand Vacuum Pump 001 589 73 21 00
6. Using a starter motor, crank the engine 8 revolutions.
7. Measure the remaining cylinder compression pressure
in the same manner and compare it with service data.
Notice
If out of standard, do cylinder pressure leakage test.
8. Remove the compression pressure recorder.
9. Install the fuel injection nozzle.
