Car overheated took to a shop and he said it was the timing gasket and radiator on 2002 Mercury Sable

I would like to know how much that should cost to fix? He quoted $1500. This is the first time the car has run hot. He topped off my fluid and told me to keep an eye on it and I have not see it go down yet and it has been a week.

Asked by for the 2002 Mercury Sable
sounds to high get a 2nd opinion. should be no more than 1000.00 with new time cover if needed