sushistrip

2013 A8L 4.0T, 120k miles.

So I hooked up this bluetooth obd2 diagnostic tool to my car just to check for any hidden fault codes, but also to see what various parameters are doing (boost, oil temp, coolant temp,etc). Heading to work this morning my coolant temps were hitting nearly 216* going down the highway, 80* ambient temp, 115* charge air temp. The coolant temp gauge on the dash sits at 4/8 bars constantly, never goes over, and I've never had any warning lights.

Is 210*-215* really normal operating temp for these cars?

MP4.2+6.0

Yes. And right in there would be what I expect. Newer Audis have an electronically controlled thermostat, or rather essentially an override combined with it. It allows the water temp and thus motor to run hotter at low loads. Hotter is more efficient even though most think in conventional terms relative to overheating risk that cooler is better. Then when the computer determines there is high load or otherwise needs more cooling oomph, in a fraction of a second the electronics take over and increase the radiator flow to cool it more. Target temp for higher load is in the low 190's (F) IIRC.

sushistrip

Fantastic info, thank you! I did notice it fluctuating quite a bit, but as you said, if it is load-based then that would happen. It would drop down to right at 190.

sushistrip

Could you apply the same logic to the charge air temperature? Mine was hovering around 150* ealier, ambient being 95*.