Castrol Radicool P-OAT Premix is a ready to use engine coolant and antifreeze. It is nitrite, amine, borate and silicate free with phosphate-inhibitor technology for vehicles requiring phosphated OAT technology. Castrol Radicool P-OAT Premix is both antifreeze and coolant and offers excellent corrosion protection to all metal parts found in the cooling system of internal combustion engines. Castrol Radicool P-OAT Premix provides year-round corrosion protection, and offers freezing protection down to -37°C.