Hi Trina,
You do have a leg to stand on but you need to be careful about how you do it. Have you had your vehicle serviced with them previously? If so had they advised you that the Turbo might be on the way out?
I would also be curious to know why, if the Turbo packed it in when it was in their care, that they didn't tell you about it when you picked up your car, or call you to advise you of it and ask whether you wanted them to fix the turbo as well? Did they examine the vehicle to determine that it was the Turbo that had packed it in? or did they simply advise you of this over the phone, as if they already knew about it? Its a bit suss isn't it.
At law - when you entrust your vehicle into someone's care in order for them to service it a bailment is created. The bailee (the mechanic) has a duty of care to protect your vehicle and ensure that its not damaged during that time. I would definitely be pushing the free fix if I were you - emphasising the fact that it was working fine before you dropped it off there, and that its very coincidental that the turbo went at the same time - insinuating that it was something they did that killed the turbo. Then perhaps at worse they will negotiate some agreement to pay half or something.
Below is a link to the Consumer law brochure on mechanics. Read up on your rights as a consumer and let the mechanic know in the course of your conversations with them that you are aware of your rights and you will take it to the Department of Fair Trading or whoever is responsible for these matters in your state, if they don't play ball.
http://www.consumerlaw.gov.au/conte...loads/industry_guides/motor_vehicle_sales.pdf
