Oil leakage
 

my 2001 C320 goes through 1 quart of oil every 600-800 miles. is this normal??

Something isn't right. How many miles?

Have the car checked for external leaks. If none are found, have your dealer begin an oil consumption test. This involves changing the oil and filter, driving the vehicle around for awhile (several hundred miles), and retreiving information with SDS. This will allow them to calculate oil usage and determine the course of action to be taken. MB is pretty good about standing behind their engines, provided they've been properly maintained. Let us know what happens.

its got about 60,000 miles.........