Update. The reason the coolant level was going down and the smell was noticed was because the hose from the tank to the bottom of the radiator had a pinhole leak. The service advisor basically said 'how did you notice that small of a leak?' I've owned almost 40 cars in my life - about 50% shouldn't have been on the road. '78 Dodge aspen wagons, '70 Fords with no brakes, plenty of rusty Subarus, VW beetles. I check ALL FLUIDS almost everyday. I am scared of breaking down with the kids in the car. I had the spark plugs replaced too. Total was $275.00. Just turned 201,000 miles.
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (194,000)
1999 E300 Turbodiesel (244,000 miles, dies at 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles)
2011 Audi A4 Avant (129,000 miles) hate this car!
BMW 330 xi 6 speed manual (100,034 miles)