Over the years while checking various MBs that exhibit high engine temperature, I've found that the coolant ratios are NEVER 50/50% but usually 30/70% [water/af].

As you know, coolant doesn't cool the engine so that excess amount of af directly contributes to higher operating engine temperature.

Personally, I use 60/40% ratio [I use MB af] with a bottle of Purple Ice. For So Cal that ratio is recommended. BTW, always use distilled water!

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Regards . . . . JimF
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'94 S500 Cpe

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