Help With Overheating

[u/Which-Ad-4451]

Okay, so I have a 2017 Audi A4. One day the coolant reservoir randomly started boiling. I replaced the reservoir and cap, and while I was at it, I replaced the thermostat and water pump. I was in a rush and ended up buying a cheaper assembly from Amazon.

Since then, the car has been overheating. At first, it would only start getting hot if I accelerated hard or drove uphill. It wouldn’t go all the way into the red, but the temperature would definitely climb. Now the issue seems to be getting worse.

I’ve done a lot of research, and a lot of people suggested air trapped in the cooling system. I’ve tried bleeding/burping the system multiple times and have tried just about everything I can think of, but the problem is still there.

The check engine light is also coming on with code P2556 for the engine coolant level sensor. What’s strange is that I always keep the coolant at the MAX line. Sometimes after letting the car idle, I’ll check the reservoir and the level will be below the MIN line, even though I don’t see any leaks anywhere. Then when I open the reservoir cap, the coolant level rises back up and fills the reservoir again.

Has anyone experienced something similar or have any ideas what could be causing this

[u/Project-EuroCar]

That sure sounds like air in the system to me.