Is there a measure for the 50/50 ratio? Such as when the coolant is tested for how low its freezing protection goes?
A bit more on topic, I just have gone through overheating problems on the 91 300e. I had replaced the thermostat 6 months ago and the radiator was rebuilt 2 years ago. I couldn't figure it out.
Finally I
replaced the radiator and Tstat and all is well.
Haasman