W219 CLS - Power Steering Problem?

[Peter C1974]

2007 CLS 320CDi, 67k miles.

Whilst parking up this afternoon and turning the steering to full lock the auxiliary belt started chirping. As soon as I let go of the wheel the noise stopped. With the engine speed increased above 1k there was no noise on full lock. I drove home (about 5 miles) and turned the steering full lock again there was no noise.

Earlier today I drove 80 miles including 3 hours in London traffic. Time for fresh PAS fluid? Could the pump be on the way out? I assume the auxiliary belt tensioner is not to blame?

Any ideas guys?

Peter C

 

[om613]

Peter, I'd start by checking the fluid level, then the belt condition for cracks.
Look down at the rack gaiters on each side, any oil there?

Yes...I had to change my rack on the drive!

 

[LostKiwi]

You should never hold the steering wheel hard against the end of the movement as you'll damage the power steering. This applies to any car.
The power steering uses a hydraulic pump to provide the power assistance and when it's held hard on full lock the pressure in the pump builds up to the point the pump strains to operate. It also puts huge forces on the steering components in general .

 

[Peter C1974]

Peter, I'd start by checking the fluid level, then the belt condition for cracks.
Look down at the rack gaiters on each side, any oil there?

Yes...I had to change my rack on the drive!

With the engine warmed up the PAS fluid level is exactly on the Max mark. Auxiliary belt is absolutely fine, no cracks.