hi all,any help with my 2001 4.4i (158000km) loosing coolant fluid. it dosent leak , but seems to be topped up with 500ml every 500km. the warning message "check coolant level" comes up on the dsiplay to prompt me. cars runs well with no overheating problems. any ideas?2 years ago i changed the radiator and hoses due to a cracked radiator.is it time to trade-in?thanks