Coolant is a mixture of water and antifreeze. Under normal conditions, it is a mixture of 50 percent water and 50 percent antifreeze, but under extreme cold weather conditions, as much as 60 percent antifreeze can be added. Mixtures above 60 percent may reduce cooling effectiveness and reduce heat transfer capability of the coolant. For reasons of anticorrosion protection and to raise the boiling point, the coolant must remain in the cooling system all year round.
Regardless of mileage, replace the coolant every two years since the degree of corrosion protection gradually drops with time.
Antifreeze approved for use in the MBE 900 engine is a mixture of ethylene glycol and corrosion inhibitors. Antifreeze containing ethylene glycol and corrosion inhibitors is known as fully-formulated antifreeze.
Note: Do not use propylene glycol.
Fully-formulated antifreeze has the following properties: