My A6 has recently (last month) started running hotter than normal, particularly at speed. Around town the temp is generally 206-210 but when I get on the highway at 70 mph it goes up to 222 at 75 around 226 and 80 around 228. It did not do this before. I am measuring using torque pro and a cheap bluetooth obd2 reader. My cheap vag-com knockoff cable and vcds-lite show around 95-99c around town (ambient air is around 35c).

In the last year we have replaced the water pump, timing belt, temp sensors (x2) and thermostat. We have just recently replaced the fan clutch (the electric fan is running, sounds like a turbine engine at times), the auxiliary water pump and a few hoses that were getting degraded.

Before we tear apart the whole front end again to check and replace the thermostat again, besides the radiator, is there any other part we should be checking?

The only codes in the engine are related to the evap purge valve (p0441 and I have one ordered and will replace soon). Idle is weird, sort of rolling between 680-720 rpm) and the engine stumble on occasion. Fuel mileage is around 20-22 on the highway which is a little low.

Just yesterday while on a brief run on the highway at 70-75mph, the temp was swinging between 210-228 on the tourque display every 30 seconds or so but the needle did not move from near the 1st mark past middle.

For what it is worth, the engine does not smell hot and there does not appear to be any excessive expansion or gurgling in the expansion tank. We replaced the cap recently as it had degraded over time. We just replaced the coolant with the correct 50/50 mix and bled the system.

 

Pulled the front off again and it is not the water pump or the thermostat. Time to replace the radiator I guess. ugh.