Third Gen Thermostat Temperatures
Q: How hot does my thermostat run?
A: Stock thermostats on 3rd generation cars are 195 degrees. If you want to go colder, you must change the PROM. This is due to the computer having preset temperatures to determine warmup and fan start conditions. A new PROM in conjunction with a thermostat change will allow the car to maintain a cooler temperature by moving the fan start temperature down to within the range of the new thermostat. In addition, most PROM upgrades will lower the warmup temparature so that the computer will not think that the engine is constantly in warm-up (enrichment) mode. Changing the thermostat without changing the PROM can lead to drivability problem and less-than-expected results, but this varys with the application.