With all due respect to Duke and others of the no-additives-are-necessary school, I beleive the correct answer is "it depends." What is your car?

In general, a fresh anti-freeze mixture will provide all the heat transfer and corrosion protection you need. That said, MB has had several recommendations over the years which even today seem to make sense. To my uncertain knowledge, they have never recommended the Water-Wetter additives. But, if one checks the maintenance sheets for earlier cars, for example my 117-engined 1972 SL, you will see their recommendation is to change anti-freeze at 30,000 miles and add an anti-corrosion oil to the mix. These are the water-soluble oils that are still readily available at the Checker/Autozone/Napas of the world.

Some of these recommendations were developed back when our cars were all metal, no plastic radiators, etc. Most were good then and are still good today.

230/8