I am a noobie with a 2007 Subaru Outback 3.0l, 131000 kms, which has developed a strange problem with the power steering. When the car is cold there is a little noise in the pump when turning the wheel hard left or right and when the car is hot this noise disappears.

Stranger still, and this is the real problem, I gradually lose power steering assist when the car warms up and especially when driving at slow speeds with many turns e.g. city driving. It gets so bad that I have to manhandle the wheel into the driving straight position after each turn. Yet if the car is parked up for a few hours and has had a chance to cool down, the steering returns to normal until the car heats up again. I have replaced the belt and checked fluid levels, but the problem persists.

Any ideas for fix would be welcome.

For a few years around that time these had some issues with an o-ring seal on the return hose to the pump allowing air into the fluid. The air causes the noise on startup, and can cause hard steering when cold by it usually goes away when its warm.

 

I would suggest a fluid flush after replacing the oring on the return hose where it attaches to the pump.

Hi. Thanks for the response. I will replace the o-ring and flush the system as suggested and will keep you posted.

... When the car is cold there is a little noise in the pump when turning the wheel hard left or right and when the car is hot this noise disappears...

 

Also, check for a Loose / slippery Belt.

 

Kind Regards.