Hello, was last in the free workshop and with payment was informed that I should soon also change the coolant, 60 EUR offer. I check at home and see: the manufacturer indicates change after 10 years. Car is only 5 years old!. Does the workshop now only want a follow-up order and has just bought too much coolant or can the coolant have actually become bad already after half the deadline (additive tired, etc.)? And if so, what ? Greetings Dirk