Pull one of the radiator hoses off and see what it looks like inside. If its pretty clean I don't see how a flush will hurt you. My cooling system is only 2 years old, but I am going to run some Prestone flush through mostly for the heck of it.

One thing that you should do is remove the radiator and clean the fins. They become clogged with crap and cooling is grealty affected.

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2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200