About 24 months ago the vehicle had an oil change performed by the local dealership. Vehicle has been serviced there since new and had never had internal engine problems. It is suspected that the technician failed to re-install the oil filler cap and this wasn't corrected until 6 months later at the next oil change. Dealer failed to document this incident. When owner's son happened to inspect the car he found oil stains under the hood and only 2 quarts of oil in the crankcase. Since then, the engine has been diagnosed with high crankcase pressure, high oil consumption and a damaged catalytic converter. Manufacturer claims no factory defect and dealer claims no improper service and blames problem on manufacturer. Oil stain evidence under the hood points to missing oil cap.Engine has internal damage and currently needs replacement and close coupled catalytic converter has lost efficiency due to phosphate poisoning from high oil consumption. Repairs at the dealership will cost more than $6000.