Sam Mcnair
New member
I have a 1989 mustang with the 2.3 Liter engine, auto transmission, and air conditioning. I have twice replaced the thermostat with a 195' F unit (recommended). I the heat of the summer the car will not warm up to much more than 170'F to 180'F even with the AC running. The only way i can get it hotter is to block off the radiator air flow which kills the AC operation. Sitting still with AC on, the trans in Drive and at fast idle, with the cooling fan off i was able to get it to go to 185'F. Gage accuracy has been verified. Car is supposed to run at around 205" to 220'F. Fuel control requires 185'F to get out of start up mode. Thus performance and fuel mileage is poor.