Power steering fluid loss

1999 Mercury Sable LS, 104K miles, A/T, 24V Duratec engine. Every 500 miles or so I need to top off the power steering fluid (about 3-4 ounces). There is no fluid leak on the ground where I park. Where could the fluid be going? or leaking?

It’s probably leaking when you are at highway speed and the engine and pump run much faster. A few drops can quickly mount up to 3-4 ounces that way.

Your mechanic needs to test the entire system; when the car us up on the hoist, it is easy to identify here there might be a leak.

The power steering fluid might leaking out of the rack and pinion seals into the rubber boots for the inner tie rod ends. Have the boots loosened from the rack and pinion assembly to see if fluid runs out.

Tester

P.S. fluid with stop leak can be effective here…

Thanks to all. I’ll give the stop leak a shot.