Trunk springs can break and cause the trunk lid to fall back down when opened.
Car Problem Reports
Mercedes-Benz C230 Trunk Springs May Break and Cause Trunk Lid to Fall When Opened
Mercedes-Benz C230 Problem
Average Mileage: 95,958 mi (60,000 mi - 110,235 mi)
Visitor, 1998 Mercedes-Benz C230, 95,000 mi
Trunk spring bracket broke.
Visitor, 2000 Mercedes-Benz C230, 60,000 mi
The spring did not fail, but the tab that it connected to just snapped off a nice crystalline fracture. Was able to reattached to another area & has been working fine. Not sure as to if this is a problem of MFG or due to a prior accident the vehicle had before we owned it. For what it is worth, the CARFAX did not show the vehicle as having been in an accident at the time of purchase. The accident report was pulled up later by one of the service advisors that was trying to buy the car for his daughter. We were not happy about that as we paid a little higher price for the car as it showed a clean FAX report & it had very low millage. The other side of the story is my gal was employed at the dealership that we bought the car from, nice place, nice people....., So, if the dealership owns the body shop, I guess they can hold the paper work back till after a sale. Look a used car over very carefully & watch out for this system error.
Heard loud pop. Trunk lid hard to pick up. Assuming that it is the spring (which is hidden) or something attached to it.