Download
Table of Contents > Descriptions of work > 4.67 Natural gas system: inspect natural gas tank for corrosion and leakage

VW Passat B7 Service Manual ➜ 4.67 Natural gas system: inspect natural gas tank for corrosion and leakage

Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
– Press ignition coils with output stages on spark plugs until stop  
by hand. They must be felt to engage.  
– Install engine cover panel.  
4.66.4  
Spark plugs: renewing, 6-cylinder FSI  
engines  
Carry out following procedure:  
– Release connection locking device carefully using assembly  
tool - T10118- and pull off connector.  
– Fit puller - T10095 A- onto ignition coils with output stage and  
remove them.  
– Unscrew spark plugs using spark plug socket - 3122 B- .  
Note  
When installing new spark plugs, regrease ignition coils with  
output stage using silicone paste ⇒ ETKA .  
The applicable silicone paste is stated in the ETKA along with  
the corresponding ignition coil and/or spark plug.  
– Apply a thin bead of silicone paste on the circumference of the  
sealing hose of the ignition coil with output stage -arrow-.  
– Install new spark plugs using spark plug socket and extension  
- VAS 3122B- .  
– Screw in new spark plugs using spark plug socket and exten‐  
sion - 3122 B- .  
Note  
Spark plug designation and specified torque, »Power unit« ⇒  
Power unit; Rep. gr. 28 ; Test data, spark plugs »Test data,  
spark plugs«.  
Please observe disposal instructions!  
– Press ignition coils with output stage onto spark plugs.  
– Slide connectors onto ignition coils with output stage until they  
can be heard to engage.  
4.67  
Natural gas system: inspect natural gas  
tank for corrosion and leakage.  
Special tools and workshop equipment required  
170  
4. Descriptions of work:  
Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
♦ Gas leak detector - VAS 523 003-  
♦ Mirror  
♦ Battery lamp - VAS 6901-  
♦ Leak detecting spray  
WARNING  
For reasons of safety, service and maintenance of the natural  
gas system may only be meticulously carried out by specially  
trained personnel.  
Natural gas is highly flammable and, in combination with air,  
creates a combustible mixture.  
There must be no open flame or source of ignition near the  
natural gas system.  
Inhaling natural gas can lead to light-headedness and lung  
damage. High concentrations may lead to suffocation due to  
lack of oxygen.  
Natural gas is NOT odourless because a gas having a strong  
odour is added.  
Condition for testing:  
♦ All parts of the natural gas system to be checked must be  
reached easily.  
♦ The exhaust gas warning lamp in the dash panel insert must  
not light up and there must be no entries concerning natural  
gas in the event memory of the engine control unit.  
♦ Working environment free of draught  
4. Descriptions of work:  
171  
Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
Note  
Every draught of air above 1.8 km/h (slight gust of wind) will  
result in falsification of the measuring result. Therefore, it is  
essential to work in a draught-free environment.  
When working on the natural gas system always ensure for  
tidiness and cleanliness!  
Inspection  
– Remove underbody cover. ⇒ General body repairs, exterior;  
Rep. gr. 66 ; Natural gas tank covers  
– Check underbody trim from inside for soiling and clean with  
normal workshop cleaning agents if needed.  
– Check the natural gas system for damage, corrosion and se‐  
curity.  
– With the aid of a mirror, inspect complete natural gas tank.  
– For German market only: make sure gap between natural gas  
fuel tank and fuel tank shut-off valve is sufficiently waxed  
⇒ page 175 .  
Applicable procedure for assessment of steel and CFRP fuel  
tanks: ⇒ Gas engines - general information; Rep. gr. 20 ; Fuel  
tanks; Damage assessment catalogue for natural gas tanks  
– Check whether the natural gas tank cover in the luggage com‐  
partment -arrow- is damage-free.  
Testing for leaks  
– Start engine to set pressures in gas system to operating state.  
For the leakage test, the engine can be switched off.  
Caution  
♦ Pressurised natural gas may escape from natural gas  
tanks.  
♦ Natural gas is highly flammable and, in combination with  
air, creates a combustible mixture.  
♦ Close fuel tank shut-off valves manually. ⇒ Fuel supply  
system – natural gas engines; Rep. gr. 20 ; Fuel tanks;  
Closing fuel tank shut-off valves N361/N362 manually  
172  
4. Descriptions of work:  
Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
– Using gas leak detecting system - VAS 523 003- , check the  
indicated test locations -arrows- for leaks. It is absolutely nec‐  
essary to check all threaded connections of the gas system.  
Note  
Refer to operating instructions for the gas leak detector - VAS  
523 003- .  
With the gas leak detector - VAS 523 003- it is only possible  
to determine whether gas is present in the air immediately  
surrounding the area being tested.  
If the gas leak detector - VAS 523 003- detects a leak, a leak  
detector spray must be used to prove conclusively whether the  
gas is actually escaping from the vehicle system. When a leak  
detector spray is used, no bubbles may escape from the  
sprayed area within a test period of 3 minutes. Should leaks  
occur, these must be repaired, after which the gas system  
must be retested.  
Test locations  
4. Descriptions of work:  
173