2003 1.8L engine has a defective head design.
If it hasn't been replaced with the updated version, I'd dump it.
Tons of threads on this.
2002 C230 Sport Coup
ASP Pulley-Supersprint Header-Remus Muffler-
TEIN SS Coilovers
AMG; Wheels, 22mm AMG Front sway bar, HR 19mm rear bar, C32 Brakes
Tinted Windows- 2005 Tails, Grill & Blinkers-Clear Sides
Clear Fogs w/Philips Crystal Vision bulbs
Renntech style Spoiler
Supercharger Muffler Deleted!
"Aero Turbine" AR20 Rasp Eliminator (Resonator)