Thanks for the helpfull input everyone. Since I did not own the car last summer, I have no basis for comparison. I know htat the newer engines run a bit hotter, but I do not what to explore how close to the edge you can go before you do some hefty damage. But for $8 (Water Wetter) and a coolant change it sounds like the right type of insurance policy to take out.
Dean: Where did you get the water wetter, my dealer does not have it.
94 E500 (Silver/Black)