Try swapping out the Coolant temp sensor located in the front of your intake runners. Very common that they go bad. We fixed this issue last week when a friends engine overheated. Swapped it out with a spare one I had laying around and that was fixed.
The car wasn't overheating, just a bad sensor saying it was.
Go to the junk yard and get a few of these or by new ones for $10-15 bucks.
