I have an 02 taurus the p/s fluid foaming and overflowing when you shut the vehicle off , changed the p/s pump due to p/s going out, now the foaming up over flowing, it will literally squirt fluid out the air hole in cap, I assume that was the problem before, but changed it without noticing that, I was going to put another p/s pump but reading online it could be a problem with the rack, I am not one to throw parts at a vehicle, so any help is appreciated Thanks

 

You got air in the system and now the pump makes whipped cream out of the power steering fluid.
A quick search brought this up:
"this could be a very easy thing to fix. if your car's been sitting for a while the lines just might be backed up or have air in them. all you need to do is bleed the lines. Start the car and fill the power steering reservoir and while the car is not moving turn the steering wheel all the way to the left then all the way to the right. do this 15-20 times and the lines will be bled."
"On top of doing this, it also helps immensely to keep the RPMs up around 3K. I couldn't ever get it to completely bleed at idle."

And my suggestion when doing this: Use the correct fluid. My Windstar uses ATF, not power steering fluid. Check the manual. Put the front wheels on some thick plastic bags and apply the parking brake. That lowers the required steering input and protects the tires. Move the steering wheel slowly and evenly.

Good luck!

 

Sometimes in the middle of the process shut the engine down and go have a cup of coffee.This allows a good portion of the small air bubbles trapped in the fluid in the reservoir to rise to the top .

 

did you find the fix for your problem