CITROEN C4 Cactus Handbook & Instructions page 222

Checks
Oil grade
Before topping-up the oil or changing the oil,
check that the oil is the correct grade for your
engine and conforms to the manufacturer's
recommendations.
Topping up the engine oil level
Refer to the "Petrol engine" or "Diesel engine"
section for the location of the oil filler cap in the
engine compartment of your vehicle.
F Unscrew the oil filler cap to reveal the filler
aperture.
F Add oil in small quantities, avoiding any
spills on engine components (risk of fire).
F Wait a few minutes before checking the
level again using the dipstick.
F Add more oil if necessary.
F After checking the level, carefully refit the
oil filler cap and the dipstick in its tube.
220
After topping up the oil, the check when
switching on the ignition with the oil
level indicator in the instrument panel
is not valid during the 30 minutes after
topping up.
Engine oil change
Refer to the manufacturer's service schedule
for details of the interval for this operation.
In order to maintain the reliability of the engine
and emission control system, never use
additives in the engine oil.