For overheating problems you should not be jumping from mechanic to mechanic. You would be wasting your time as the basic checks do not show anything and when overheating occurs, you should immediately go back to the last mechanic and let him know the situation.
By going to a new mechanic, he would just top up the coolant and checks would show nothing again.
Since you have coolant losses issues, you need to be checking for leaks and as Saturntech9 mentioned, test for carbon/exhaust gases in cooling system.
Wednesday, January 9th, 2013 AT 1:09 PM