Replaced the PAS pump back in Feb, result of very heavy steering. I bled the system through multiple times.

After every run out I am getting air back into the system, its quiet when it first sets off. I can see no leaks LP/HP side and no loss of fluid. Steering is quiet when cold and first setting off. I can only assume this is the potential cause of the original pump failure. Model is 2008. Seeing a slight loss in PAS power once warm and air bubbles which would be expected vs cold.

Anyone got experience of this - could it be the LP supply and return lines, bottle or possible the fluid cooler at the front? Surely any air leak on the HP side would see fluid loss?

I did also change the servotronic module originally when trying to resolve the heavy steering - no leaks on there.

Fluid has been flushed. I re-checked the LP hose connections and they look good.

I've seen a post on the fluid cooler - really want to rule out everything else before removing the front of the car.