Ok so I just purchased a used 08 B7 Avant, she's a beaut, it had 97000 kms on it when I bought it and it has 102000 kms on it now. I loaded up some buddies in it and packed all our snowboard gear and drove to Vermont (jay Peak) from Toronto this last weekend. Everything was great except on the way home we decided to stop in Montreal and grab some smoked meat. What I noticed was at the first set of lights we hit in the city, I had no power steering (ps) when the car was at idle but as soon as I gave it some gas I had full power steering. The downtown was packed so we immediately jumped back on the highway and drove to the nearest service centre. Once there I did an inspection. There was no noise coming from the power steering pump, the lines were connected good and there was no visible leaks either in the engine compartment or under the car. I checked the fluid level and it was exactly in the middle of where it should have been. I didn't check the colour of the fluid though. I then started the car back up and it had full power steering even at idle. We then drove the rest of the way home 500+ kms and the problem never returned. Has anyone ever had this problem before?
I have a theory about this and tell me if I am crazy. Just before we left the ski hill we were in a big empty parking lot that was covered in snow. We spent some time doing some low fat dough nuts in the parking lot. We held the RPMS steady between 4000 and 5000 rpms. My theory is that during the high rpms the power steering pump began cavitating and created some air bubbles in the system. And when I opened the reservoir I released the trapped air in the system. Is that even plausible or am I looking at some kind of faulty relay somewhere that is flaky?