5 Series E34 518g (M43) TOUR
13 80 ...
Maintenance and repair of CNG vehicle
Due to the new natural gas technology used in BMW vehicles, the scope of maintenance and repair work on the 316g
compact and the 518g pass be extended.
In addition, operation with natural gas imposes special requirements on the engine oil:
-
The formation of deposits on valves an combustion chamber surfaces in natural gas operating mode cannot be
prevented by the use of fuel additives (these additives are not present in CNG). The oil should therefore only
contain an absolute minimum of sediment-forming components.
-
The high proportion of methane in natural gas can also cause problems leading to sediments forming from the oil
used in petrol engines.
For these reasons, a special engine oil must be used in the CNG vehicle. This can be obtained from the BMW Parts
Service.
Pre-delivery inspection
The 316g compact version of the E36/5 model, the petrol-engined version of which did not have to pass a pre-delivery
inspection, is required to undergo the following inspection procedure after approx. 2000 km.
The pre-delivery inspection specified for the E34/2 after approx. 2000 km has been extended by the following point for
the 518g touring.
1.
Adjustment of the low-pressure regulator
The differential pressure gauge is used to adjust the pressure difference between the suction pipe and both
stages of the low-pressure regulator to the appropriate nominal value (refer to "Adjustment values for the low-
pressure regulator" in the Repair Manual).
1.Oil service
In addition to specified operations, Point 1 (adjustment of the low-pressure regulator) only has to be performed
on both vehicles during the 1st Oil Service.
Inspection 1
During Inspection 1, in addition to the usual scope of inspection, the additional Point 1 (adjustment of the low-
pressure regulator) should be processed.
In addition to this, the vehicle should be subjected to a leak and pressure test and the compressed gas system
should be given a corrosion test:
2.
Leak test on the CNG system
The leak test is performed in two steps
-Leak test using the compressed air provided in the workshop and the appropriate special tool. This is performed
by spraying the accessible screw connection points with leak tester spray (refer to BMW Parts Service).
-Pressure test with compressed gas tank at least 75
%
full (150bar). This is performed by spraying the accessible
screw connection points with leak tester spray (refer to BMW Parts Service).
3.
Corrosion of CNG compressed gas tank and tank frame
Check whether condensate on the CNG compressed gas tank (beside annular bracket on frame and on
connecting elements between frame and vehicle) has caused corrosion.
Corrosion is not defined in this case as superficial fretting corrosion. Corrosion has to cover a large area with
potential material loss to classify as a reportable corrosion problem.
RA Maintenance and repair of CNG vehicle
BMW AG - TIS
15.01.2013 13:13
Issue status (12/2007) Valid only until next DVD is issued
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