Having an issue with the car (2000 Auto) overheating when stuck in traffic or waiting at a drive-thru for a long period of time. The car will gradually begin overheating, but as soon as i get back on the road the needle returns to normal. I dont know if this is related but my heater also goes off and on, works fine when driving but if i stop will blow cold air. Planning to replace the thermostat this weekend, also want to to a radiator flush but i keep reading different techniques on how to do so. The haynes manual shows me one way, this link http://www.mikefordmustang.com/write...on-mustang.php shows me another. Any help on the above problems would be great thanks

 

Get the Prestone radiator flush and follow the directions on the back, after you flush it, change the thermostat with a factory unit.

 

If it cools down while your driving, and heats up while your stopped, then its probably your electric cooling fan. When it heats up when stopped, do you hear the fan kick in? If not, there's your problem.

The radiator flush etc is still a good idea though, especially if it hasn't been done in a couple years.

 

+1 to the fan.
+2 to doing the flush anyways.

To test if your fan works set your A/C to MAX and check to see if its on.
Your fan will always come on when the A/C is set to MAX. If it does not then you have a bad fan.