Very negligent and irresponsible. Let them know engine had old sludgy oil stuck to engine for last 3 years and did not pass emmisions. I wanted their opinion on the possibility of passing emissions. After cleaning oil control valve and all passengers in cylinder head. They told me to drive the car and bring back for emmisions check. I drove the car about 15 miles and the engine locked up as a result of work performed. They refused to take responsibility after never letting me know this could happen. They did not advise me that their tinkering could render my car undrivable. NOW I HAVE NO CAR. They should have informed of the risk and given the choice of deciding.