Wow, so he managed to purchase the car, drive it home, notice a rattle, take it to a mechanic, them to immediately diagnose the bottom end is gone and quote him for the work all in the space of just a few hours?
Tell him to hop it. If you know that the car was fine before, that should be the end of it.
We had the same, some woman came around to test drive my mum's old Saab. She didn't bring insurance with her (Sorry dear, your word isn't good enough i'm afraid) so natually no test drive. But she got to be passenger and let my mum test it for her with whatever she wanted to do.
She was happy with it, went away and then called back a day later saying there was something wrong with the gearbox and it felt like it was going to drop out and that she wanted her money back. Kindly told her that there was nothing wrong with it for the past 2.5 years my mum had it so unfortunately nothing we could do.
It really was a straight car. The only reason she got rid of it is because she had a bit of money saved and bought a new BMW. She really did like the Saab though, even though i reminded her constantly of how rubbish it was.
Bottom line is that that car was perfect when it left us, so either something happened on the womans journey home, or the more likely scenario is that the car had characteristics that she wasn't accustom to, which she thought meant it was broken.
In your case, some cars just have engines that rattle more than others - doesn't mean the bottom end has gone!
