I always use the cheapest green coolant I can get my hands on and distilled water. Never had a problem. I swear every euro manufacturer has its own proprietary fill in the blank color coolant. I've heard the same story with BMW, Volvo and Audi owners. If you don't use the ultra special dealer only coolant your engine will blow up and your children will be born with hooves. I call BS.

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CENSORED due to not family friendly words