Drjbrob

Hello all. I have a 2008 A6 with the 4.2FSI. I am experiencing a strange issue. So far while driving there are zero symptoms of the car misfiring or running problems. The vehicle sounds and drives perfect. Only issue I am seeing is my coolant temperature is not going above the 1/4 tick mark (154°F) . My scanner reads my coolant temperature at 154 Fahrenheit and it does not seem to go higher while I am driving highway or town.if I park and let it idle for about 20 minutes it starts to heat to about 170F ish then will start stuttering/misfiring and the engine shuts off completely. If I let it idle to this point it will sometimes throw a code P0087 . But when I let the car cool down and start it back up again/ start driving the engine cools black down to 154F and the car runs perfectly again. Any ideas or Thoughts? Thank you all for your time.

kombifan

Thermostat? Try replacing that first

Then do a coolant flush at the same time.

jonzie77

I agree with Kombi on the thermostat, it's probably stuck open. It could also be one of the coolant temperature sensors is wrong about what the temp is and is giving the ECU bad info.