DIAGNOSTIC SHEET

Problem:
Models:

Reference BOLs:

MAS002116 - N° 002.2020

Oil leak/wetting in the gearbox area
All Models (Sedan) and SUV
Diesel and Gasoline
BOL801851: oil leak from the Gearbox All Wheel Drive Transfer Case
BOL1397629: engine oil leak from the clean air sleeve – second section (Diesel)
BOL1338619: engine oil leak from the crankshaft rear seal ring (gasoline)
BOL1459793: gearbox oil leak from the gearbox
Oil marks or wetting traces can be found close to the gearbox oil pan and from the oil
pan fixing screws (Figure 1).

Defect
description:

Figure 1

Conditions:

No particular conditions.

DTCs in ECUs:

No DTC in any ECU.

Troubleshooting:

Case 1, for the sole Diesel engine version.
Carefully verify whether there are sources of leak in coincidence of the delivery or
return pipes of the turbocharger lubrication, as highlighted in
Verificare accuratamente se siano presenti fonti di trasudo olio in corrispondenza
delle tubazioni di mandata o ritorno della lubrificazione del turbocompressore, come
evidenziato in Figure 2.

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Figure 2: section 01.31-3 of the Spare Parts Catalogue.

Verify the possibility of oil leak from the intake sleeve compressor inlet gasket (CLEAN
AIR SLEEVE - SECOND SECTION), as highlighted in Figure 3.

Figure 3: section 01.41-3 of the Spare Parts Catalogue.

If oil leak can be found in the areas shown in Figure 2 and Figure 3 proceed with the
repair as required.
Otherwise, should no oil leak be found, proceed with Case 3.
Case 2, for the gasoline Vehicles only.
Lift the Vehicle on hoist and check whether there is oil leak in the connection area of
the pipes with the gearbox and to the WTOC (Water Transmission Oil Cooler, engine
coolant-gearbox oil heat exchanger), as highlighted in Figure 4.
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Figure 4: section 03.50-2 of the Spare Parts Catalogue.

Watch out careful attention to leakages in coincidence of the junctions of the pipes
with the gearbox itself, as shown in Figure 5.

Figure 5

Inspection the WTOC (Water Transmission Oil Cooler, engine coolant-gearbox oil heat
exchanger) as shown in
Ispezionare il WTOC (Water Transmission Oil Cooler, scambiatore acqua-olio cambio)
come mostrato in Figure 6.

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Figure 6

If oil leak is found in the junction of the pipes with the gearbox or in the WTOC,
proceed with the disassembly of the gearbox and then of the two pipes, finally
perform a bubble test in the following way:
1. Fill a bucket or a basin with water.
2. Immerse the pipe in the water with the hands and completely obstruct one of
its ending by a finger.
3. Insert the tip of the compressed air gun in the free end of the pipe and push
air in the pipe.
4. If air bubbles originate in the water, this means that the pipe has internal
damage.
5. If air bubbles do NOT originate in the water, please attempt to gently bend
the pipe in order to replicate the fitting of the pipe in the Vehicle, repeating
the steps from 2 and 3.
6. If air bubbles still do NOT generate in the water, replace the WTOC and the
relevant pipes, prepare the pipes for the shipping for parts return for further
analyses. Clean eventual oil residues and perform a road test in order to verify
whether the problem was solved.
Case 3, in general.
1. Verify the gearbox oil level.
If the gearbox oil level is low, restore the level to the original one and take
note of the amount of added oil.
If the gearbox oil level is compliant to specifications, this means that the
leakage doesn’t come from the gearbox.
2. Carefully clean and dry all the areas where talcum is going to be applied,
in particular the area where the wetting is.
3. Perform a road test making the oil reach the working temperature in
order to point out the potential source of the leak.
4. Check again whether there are leakages.
5. Potetial areas of leakage are as follows.
Case 5.1: interface gearbox-gearbox oil pan.
Casoe 5.2: interface engine – gearbox.
Caso 5.3: interface gearbox – AWD transfer case (AWD version only).
Caso 5.4: rear-end of the casting of the gearbox (RWD version).
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In Case 5.1.: gearbox oil pan kit must NOT be replaced, unless it shows evident
physical damages as a consequence of Vehicle’s accidents.
In Case 5.2, as in Figure 7, proceed as described in steps from proseguire come
descritto nei punti da 5.2.1 to 5.2.4.

Figure 7

5.2.1. Clean the area affected by the leak.
5.2.2. Verify, possibly by means of an endoscope, whether there is any oil
accumulation between engine and gearbox.
5.2.3. In case there is oil accumulation, remove the gearbox according to
Workshop Manual procedure and verify the correct sealing of the
crankshaft rear seal ring.as in Figure 8.
5.2.4. When performing the check, make sure there is no oil leak from the
threaded oil plug on the engine block highlighted in Figure 8.

Figure 8

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Figure 9

If the area mentioned in steps 5.2.3 and 5.2.4 shows wetting or obvious leakage,
repair as per Workshop Manual instructions, provided to have received authorization
via BOL.
In case 5.3, as shown in Figure 10, send a BOL report as Support Request.

Figure 10

In case 5.4: replace the gearbox output seal ring, as shown in Figure 11, according to
instructions of Workshop Manual and perform a road test in order to make sure
problem was solved.
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Figure 11

Considerations:

Attach pictures and/or videos to Blue On Line report.
Concerning the oil leakages from the oil heat exchanger pipes, it is requested to
perform a bubble test, immerging and bending the pipes in water, blowing
compressed air with a compressed-air gun in the pipe itself.
It is recommended to bend the pipe in one direction as well as the opposite one, even
by a small amount, since if a cut is there in the inner side of PTFE
(Polytetrafluoroethylen)-pipe it might become more evident by bending the pipe.
This can give clear indication that the leakage comes from the pipes.
If wetting is there in the gearbox oil pan area as well as from its fitting screws to the
gearbox casting, it might misleadingly give impression that the leakage comes from
the pan itself, as highlighted in Figure 12.
This wrong impression is a consequence of the fact that the lubricant could
accumulate in the surface between the screw’s head and the oil pan itself, as
highlighted in Figure 13. This oil can come from other areas in the upper end of the
engine.
Should there be oil accumulation in the gearbox oil pan area, it is suggested to:
1. Remove the fixing screws of the gearbox oil pan to the gearbox.
2. Clean the head of the screws and the counterpart surface of the gearbox oil
pan.
3. Reassemble the gearbox oil pan.

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Figure 12: wetting in the gearbox oil sump screw area after cleaning, application of talcum and road test.

Figure 13: engine oil accumulation in the seat of the gearbox oil sump fixing screw.

In vent the problem is not solved, submit a BOL report as Support Request.

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