My car started randomly overheating last week. I can't seem to figure out what it is. The needle starts to move right of center at about 1/2 mile traveled consistently.

So far I have

Replaced coolant reservoir
Replaced reservoir cap
Bled 5436426236w times
Completely flushed system and replaced with audi bought g11
replaced thermostat/seal


The car will run fine for about 5 miles if I don't screw the cap on all the way pressurizing the system. Soon as it pressurizes it overheats in under half a mile. I don't know what to do

My vehicle is a 2006 a8 4.2l. Roughly 123k miles. The car isn't throwing any codes. The vehicle behaves as if there is air in the lines but I don't understand how there could be.

Oh! and I pressure tested the cooling system, no leaks.

Thanks in advance!

 

I found two ac lines behind the front grill of the driver side fog lamp that was spraying green **** all over the place. Anyone think it's possible the refrigerant isn't cycling through the radiator and subsequently not cooling the antifreeze?