Opel COMBO Owner's Manual page 258

256 Service and maintenance
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
cold regions 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.
Washer fluid
Use only washer fluid approved for
the vehicle to prevent damage of
wiper blades, paintwork, plastic and
rubber parts. Consult a workshop.
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.
AdBlue
Only use AdBlue to reduce the
nitrogen oxides in the exhaust
emission 3 154.