Hi there. I've noticed over the past 6 months that I've needed to add Power Steering Fluid to my 2000 S70 GLT (39,000 miles) every month or so. Three weeks ago, after topping off the fluid again, I brought the car to the Volvo dealer and he indicated that this was normal and there was no leak detected. However, today I noticed that the fluid level was low again (the level on the dipstick was at the Cold/Add mark). So, I again added fluid. I also noticed that as I unscrewed the Power Steering Fluid reservoir cap, there appeared to be a release of some pressure within this reservoir (almost to the point where a 'sigh' was heard). There was also (what appeared to be) a dried Power Steering Fluid residue left on the horizontal surface of the reservoir itself (I would never shut the hood of my car with a mess like that but maybe the Volvo dealer did). Does all of this add up to what the problem might be? Any assistance would be appreciated so when I bring the car back to the dealer, I can point him in the right direction.

Thanks, in advance, for your time and thoughtful insight.