Head gasket was done at 66,000 miles, the water pump at 115,000 miles, the oil is clean and clear and the cap to the tank is 1 year old.
I did hear a hissing sound near the tank on Satruday (now that I remember) and the smell began on the passenger side forward area. I know the expansion tank is there, but how active is that system in terms of fluid transfer to the upper tank and back during driving?
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)