Hello,
I just purchased a 1996 Audi A6 with 90K miles. Recently the Temperature Gauge is pegged almost all the way to the left (cold) maybe hitting the very first line. I suspected stuck wide open thermostat and time to do a timing belt job to replace belt, water pump, thermostat, et. all in one shot. In addition I was getting about 20MPG highway which is poor mileage for this car soI figured ECU was enrichening mixture to compensate for cold operating temps. Check engine light is also on.
Dealer said problem was ECT (Engine Coolant Temp Sensor) and assured me that was the reason for Check Engine Light and was also responsible for "malfunctioning temp gauge." Dealer installed ECT and then later advised me Temp gauge is still way too cold and the Thermostat is probably stuck wide open and the bad thermostat may cause the ECT to fail again. Great job dealer. I drive out of lot and 2 miles later the Check Engine Light comes back on. I took it to Autozone today and only one Error Code came up P0116 Faulty Engine Coolant Temp Sensor. Does anybody know if this new ECT with 10 miles on it is shot already? Will replacing the thermostat so computer sees normal Temperature readings solve my Check Engine Light problems with Code P0116? Why on earth would the dealer replace the ECT when it is so obvious the Thermostat is stuck wide open? Any suggestions on the proper sequence of repair would be greatly appreciated.