My 98 E320 battery lasted under 5 years, it also gave out when the weather started to turn cold. The car spent it's first two years in San Diago. I believe that the warm climate shortens the life of a battery.

A new battery and a fresh oil/filter change to 0W40 and you should be ready for the winter months.

BTW Mobil 1 0W40 is rated for year round use - not just winter months.

Since you purchased your ML320 six months ago, check the maintenance log to verify that the coolant has been changed every 3 years and the brake fluid every 2 years (from the date of manufacture).

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Ray
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles