Originally posted by: bobdole369
its still their job to leave me with a working car as a finished product.
No its not. It is their job to provide you with goods and services that which are purchased.
I don't mean to be a dick and please don't take this the wrong way - its just what little I know about the world, the US court system and our system of capitalism.
Lets say you take a car in because the thing won't run. The mechanic diagnoses the problem as "timing belt" - replaces that part and some other associated bits (gaskets and whatnot) - now the car runs - as far as he is concerned - the issue is fixed.
You take it home and a week later it stops running again - you take it back - this time its "valves" that are the problem.
Now the mechanic should have known that a timing belt will sometimes bend valves. He didn't touch the valves in your car. After he replaced the timing belt - he was done.
Now you have a second problem that costs more than the first one!
However the warranty covers whatever parts were replaced, and that labor - it doesn't include the valves here.
I'm not saying that your situation is the same as this, just illustrating that your problem may not be related to the original problem, and the mechanic probably won't touch it because he knows its involved, and it's probably not related to something he warranted.
As for what to do - if he's a dick the only thing to do is to sue him. Be prepared for a massive bill from a lawyer though.