Opel 2016 ASTRA Owner's Manual page 295

Additional engine oil additives
The use of additional engine oil
additives could cause damage and
invalidate the warranty.
Engine oil viscosity grades
The SAE viscosity grade gives
information of the thickness of the oil.
Multigrade oil is indicated by two
figures, e.g. SAE 5W-30. The first
figure, followed by a W, indicates the
low temperature viscosity and the
second figure the high temperature
viscosity.
Select the appropriate viscosity grade
depending on the minimum ambient
temperature 3 296.
All of the recommended viscosity
grades are suitable for high ambient
temperatures.
Coolant and antifreeze
Use only organic acid type-long life
coolant (LLC) antifreeze approved for
the vehicle. Consult a workshop.
The system is factory filled with
coolant designed for excellent
corrosion protection and frost
protection down to approx. -28 °C. In
northern countries with very low
temperatures, the factory filled
coolant provides frost protection
down to approx. -37 °C. This
concentration should be maintained
all year round. The use of additional
coolant additives that intend to give
additional corrosion protection or seal
against minor leaks can cause
function problems. Liability for
consequences resulting from the use
of additional coolant additives will be
rejected.
Brake and clutch fluid
Over time, brake fluid absorbs
moisture which will reduce braking
effectiveness. The brake fluid should
therefore be replaced at the specified
interval.
Service and maintenance 293