I have a 2000 Audi A6 Quattro. For the past few months Code 17704 would come on indicating Error in Mapped Cooling System. Brought the car to a shop last week and they found the coolant sensor defective and replaced it.

The shop confirmed the new coolant sensor was reading accurate coolant temperatures. When they rode the car uphill and downhill afterwards, the mechanic noted when going downhill, the coolant temperature would drop to 160 degrees F. The 1st shop thought this was too low and may indicate the thermostat may be sticking in the open position at times.

I brought it to another shop and rode with the mechanic / owner and he hooked up a $15,000 code scanner as well and we rode uphill and downhill and at the bottom of a long hill, the coolant temperature dropped to 155 degrees F. This was done on a 63 degree day. No error code came on and the 2nd shop owner suggested I research the specs for this specific model further.

The coolant gauge in the cockpit normally reads in the middle when driving.

QUESTION: Does anyone have access to true 2000 Audi A6 Quattro specs as to what the lowest operating temperature a working VW/Audi should go to safely before closing? I am not sure how concerned we should be or if we can wait until the next timing belt change. We already changed the timing belt, water pump and thermostat (supposedly) in 8/2014 and have no interest in tearing the front apart just to put another thermostat in if it can wait till the next timing belt change.


Thanks,

LP