warranty on ur first service?

Is there any warranty on your first order ($300)? If yes, you probably have a chance to reqire the garage to fix your problem for free.

As I know, the most garages will try to repalce every parts (even good parts) to grab your money. Regards to the headgasket, $600 fee is even a cheaper charge. The engine will be opened to replace the headgasket, I think.

Think about it and require a warranty on your next move.