Report them to the BBB, make them either fix it this week or return your money. Also never take it back. I run my business on the basis I will not lie to you, I will stay late, come in early, or drive 100 miles to help you out. I have run my own shop for 2 yrs now, and man, i'm almost getting to hate people. Also as far as fixing it right the first time, listen to this and if the shop you go to doesn't do it leave. Ok they should ask i.e. ; it's over heating, when at stop lights, going down the road, does it over heat fast, or take a while, also any thing else going on? Then my first step is verify the problem with a test drive or a test run, then systematically test for the problem/ diagnose it. Call customer and give estimate for approval, do work, test drive for 5-10 miles to verify problem is fixed. Now someone said they paid for work not authorized, they screwed you, you have to approve any work over $100, and the final bill cannot be over 10% of estimate without approval.