Still a bit confused about removing and replacing some of my power steering fluid on my 99 Mustang six, with 220,000 miles on it - which groans when cold. I saw Scotty recommend a full synthetic p/s fluid, but saw some stating it could hurt an older p/s pump as on my 1999. If I choose a good full synthetic p/s fluid, remove some of my old fluid from reservoir and replace it - do I want a full synthetic p/s fluid WITH a seal conditioner, though it is not leaking - because of its age? Or do I want to avoid using a full synthetic with a seal conditioner? What are some of the recommended top brands?
- Well I've never seen synthetic fluid and damage anything on a Ford. It's just a pure or fluid with less impurities that can take both higher and lower temperatures. I find red line or amsoil to be good ones
What does the maintenance section of your owner's manual specify?
Check your owner's manual. Some Ford vehicles of that era use the same fluid in the power steering system as they use in the automatic transmission -my 1999 Ranger is this way, and it takes Mercon V for both applications.
Power steering systems aren't like automatic transmissions. You can completely empty the power steering system on a high mileage system and put new fluid in without harming the system. The old fluid is dirty and starts to become a low grade cutting fluid when it hits the seals. My truck has 290,000 miles on the original power steering pump, I fully flushed the system over the summer. It groans a bit when I turn the wheel while not moving, but old Ford power steering pumps are known for that.
The confusing part is Scotty says to add a full synthetic fluid, Ford's is not full synthetic - this is support to work better in lower temps, when the power steering wants to growl. He stated this often fixes it - but if I remove some fluid and replace it with a full synthetic, will it hurt anything? One youtube mechanic was claiming it would hurt older cars. Also, do I want a full synthetic fluid with a seal conditioner? Mine is not leaking at all, but is a seal conditioner good or bad if the car is not leaking? Will it help maintain the seals?