General Repair Information

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.

In the workshop, two separate working areas are required, in which specific demands are made upon work safety and equipment, due to the differing hazards which prevail:
- Normal workshop area in which only maintenance and repair work on non-gas-bearing vehicle components is performed.
- Special workplace for gas-driven vehicles in which repair work on gas-bearing vehicle components is performed.
Therefore, before commencing an operation, the type and scope of the repair work must be checked. Before commencing an operation, it must also be checked whether the suggested repair work is in accordance with the current technological standards for maintenance work on the gas system.
Gas-powered vehicles such as vehicles with gasoline engines can be dealt with during normal maintenance and repair work (with the exception of work on the gas system). This does not apply to vehicles with a leaking gas system.
Non-gas-related maintenance and repairs can also be performed by mechanics who have not had gas training if they have been instructed by a skilled worker (member of staff with gas training) and the work has been accepted (inspected). However, the staff must be aware of the relevant national regulations and rules (for example: for Germany BGR157, GUV17.1, etc.) and have been given instruction on special gas-specific features.
The following generally applies: maintenance and inspection work on the gas system may only be carried out by trained and qualified staff in workshops set up for this purpose.
Repair work on gas system components such as pressure reducers that are not described in the service instructions is not permitted. These components must never be forced open or modified.
The service literature (replacement procedures) must be followed.
No holes may be drilled in the underbody area, from the interior of gas-driven vehicles. This is indicated by the stickers "Caution, tank system: drilling/grinding prohibited" in the vehicle interior and on the cover for the pressurized gas tanks. If there are no stickers in the appropriate places, these must be applied.
The pipe connections are manufactured to very fine tolerances. In order to check the screw connections for correct fitting, a leak test must be performed.
Because a variety of different bolts and screws are used, make sure that you are using the correct ones. Do not mix them up.
Before all work on gas-bearing components and screw connections following must be done:
- The main shut-off valve on all pressurized gas tanks must be closed
- Residual pressure in the lines should be dissipated by running the engine until it stops, if possible.
  NOTE: The lines are sufficiently discharged if, after several minutes of idling, the engine stops without the ignition being switched off.
Keep components of the gas system away from direct heat (e.g. incident solar radiation) and avoid temperatures in excess of 60°C (122°F) - risk of explosion.
For repairs on LPG/CNG powered vehicles where temperatures of over 60°C (140°F) are possible (for example: paint spraying-drying systems and infrared spotlight drying systems), the following must be complied with:
- CNG: The tank pressure must NOT be more than 100 bar (1450 PSI). Should the pressure be more than 100 bar (1450 PSI), the system must be evacuated. A nitrogen flushing procedure is however not necessary. A diagnostic tester should be used to determine system pressure.
- LPG: The gas system must be completely evacuated.
- Gas system evacuation procedures can be found in: "L Fuel System, Exhaust System"
Gas system components such as the pressure reducer must never be subjected to heat; the changes to the material properties that may occur can have a considerable effect on the operating safety of the vehicle. The gas system components must therefore not be thawed out using an external heat source if they freeze up.
Pressurized gas tanks, gas lines and all parts carrying gas must always be removed if work is being carried out during which extreme heat will be generated such as drilling work, cutting work, grinding work, soldering work and welding work, working with hot air or cutting torches etc. within a distance of 1 meter or less of these parts.
All other gas system components must be completely discharged.
Never install connections with missing closures or parts that have been contaminated with dirt, grease or moisture. Never install pipes, hoses and individual components unless the connections are in perfect condition.
Gas system components which must be loosened or removed during repair work must be properly refastened in their original positions using genuine spare parts (cable ties, clips, wiring trough brackets, etc.). Particular care must be taken regarding proper routing and secure connection of gas-bearing components.
No other components must be fastened to gas lines, e.g. wiring.
Before reusing the vehicle after repair work, the gas system must always be subjected to a leak test, as described in the Service Instructions. The corresponding work operations are to be found under "Engine Controls/Fuel".
Following assembly, the natural gas system must not suddenly be subjected to natural gas under full operating pressure from the pressurized gas tanks, e.g. due to the opening of a solenoid valve. It would then not be possible to find a leaking connection using the usual leak-detecting sprays as, due to the high pressure of 200 bar, the natural gas would blow away the leak-detecting medium from the leak point without the formation of bubbles. Due to the high pressure, leaks constitute an injury hazard.
Furthermore, all gas system components must be subjected to a functional and visual check with regard to defects such as contamination, deformation, formation of cracks, chafing, corrosion and other damage.
As cut-off devices with actuators (solenoid valves) are used, the switching function must be checked. The cut-off devices must close automatically when the ignition is switched off (audible).
Soiled parts must be cleaned and protected from ageing with suitable anticorrosives if necessary. DO NOT USE OIL.
Vehicles in which leaks in the gas system have been detected must not be handed over to the customer - danger of explosion.
Malfunctions or faults which are detected in the gas system must be remedied immediately.
Filling a natural gas-driven vehicle using a system without a gas dryer and without a filter is impermissible.
Switch off the engine and the auxiliary heater before filling the pressurized gas tank system. The vehicle to be filled must be protected against rolling by engaging the parking brake.

NOTE:

Servicing and repair work on the gas system is subject to mandatory registration, see chapter "Registration" in this document.

Escaping gas can cause injury and freezing to parts of the body with which it comes into contact. If necessary, suitable protective measures must be taken, such as the wearing of protective leather gloves.
Appropriate warning signs must be set up during operations on the gas system.
Lift and support the vehicle at the designated jacking points ONLY. The jacking points on the body are vehicle-specific. Refer to Lifting and Jacking the Vehicle in order to observe the compulsory jacking points. It is not permissible to lift the vehicle at certain components, e.g. pressurized gas tanks, carrier frame for pressurized gas tanks etc., as slipping of the vehicle could cause damage to the pressurized gas tanks or the high pressure lines.
Spraying or other application of oil or lubricants in the vicinity of gas system components is prohibited - danger of explosion.
Utmost cleanliness must be ensured during operations on the gas system, especially with regard to the screw connections of gas-bearing components. The work must be performed with the utmost care.

For cleaning purposes, only use:
- Clear water without cleaning additives
- Lint-free cloths
Several operations require special service tools that may only be utilized for the purpose specified in the Service Instructions. The use of these tools ensures safe and technically reliable repair work, as approved by GM.