248Checking and refilling levels
WARNING (Continued)
● Fires, sparks, open flames and smoking are prohibited. When han-
dling cables and electrical equipment, avoid causing sparks and electro-
static charge. Never short the battery terminals. High-energy sparks can
cause injury.
● A highly explosive mixture of gases is released when the battery is
under charge. The batteries should be charged in a well-ventilated room
only.
● Keep children away from acid and batteries.
● Before working on the electrical system, you must switch off the en-
gine, the ignition and all consumers. The negative cable on the battery
must be disconnected. When a light bulb is changed, you need only
switch off the light.
● Deactivate the anti-theft alarm by unlocking the vehicle before you
disconnect the battery! The alarm will otherwise be triggered.
● When disconnecting the battery from the vehicle on-board network,
disconnect first the negative cable and then the positive cable.
● Switch off all electrical consumers before reconnecting the battery.
Reconnect first the positive cable and then the negative cable. Never re-
verse the polarity of the connections. This could cause an electrical fire.
● Never charge a frozen battery, or one which has thawed. This could
result in explosions and chemical burns. Always replace a battery which
has frozen. A flat battery can freeze at temperatures around 0 °C.
● Ensure that the vent hose is always connected to the battery.
● Never use a defective battery. This could cause an explosion. Replace
a damaged battery immediately.CAUTION
● Never disconnect the battery if the ignition is switched on or if the en-
gine is running. This could damage the electrical system or electronic com-
ponents.
● Do not expose the battery to direct sunlight over a long period of time,
as the intense ultraviolet radiation can damage the battery housing.
● If the vehicle is left standing in cold conditions for a long period, protect
the battery from freezing. If it freezes it will be damaged.
Checking the electrolyte level
The electrolyte level should be checked regularly in high-
mileage vehicles, in hot countries and in older batteries. – Open the engine bonnet and the battery cover ⇒
in Safety in-
structions on working in the engine compartment on page 234
⇒
in Warnings on handling the battery on page 247.
– Check the colour display in the "magic eye" on the top of the
battery.
– If there are air bubbles in the window, tap the window gently
until they disperse.
The position of the battery is shown in the corresponding engine compart-
ment diagram ⇒ page 292.
The “magic eye” indicator, located on the top of the battery changes colour,
depending on the charge state and electrolyte level of the battery.
There are two different colours:
