Older engines use coolant that is Blue/Green later engines use Pink, Pink coolant can be used in older engines but Blue/Green cannot be used in later engines. Always use plenty of coolant. Never remove the cap from a hot engine, the cap may 'fly off' on releasing and hot coolant will burn your hand, if you must remove the cap, cover the cap with a suitable cloth, screw the cap slowly to release the pressure, then carefully remove the cap, do not put finger in hot coolant.