Power Steering Fluid

1997ThunderbirdLXV6

Veteran Poster
Joined
Sep 22, 2023
Messages
810
Location
Richmond, VA
Country flag
Ok...of course the answer is always: follow the manufacturer's recommendation.

In reality, Mercon V doesn't seem to do a good job in my steering.

Generally, I prefer light steering effort. Quietness is also appreciated.

I went through a few stages, each time siphoning out the fluid, which achieves about a two-thirds replacement with patience.

  • Original fluid, probably Mercon sans V: steering was on the heavy side, but this was also before the ball joint replacement
  • Replaced with Motorcraft Mercon V: marginal improvements, still sort of heavy, at a standstill occasional momentary rpm drops when steering quickly
  • Replaced with Super Tech Mercon V: no change
  • Replaced with Valvoline Maxlife ATF: slightly lighter, but not quieter; if anything, a bit louder
  • Replaced with Bar's Leak Power Steering Repair: noticeably lighter, but not quieter
I'm somewhat satisfied at this point, but some of the whine bothers me. At a standstill, idle rpm, its completely quiet. However, revving even slightly higher, e.g., making a turn, say 1,200 to 1,500 rpm while turning, there's whine. It's not a loud high-pitched whine but rather a subtle mechanical whine.

So it's probably nothing. I just wish it was quieter.

Is there a miracle fluid that can do that?
 
On my 96 Tbird I did a partial Mercon V change and added this stuff... It was fairly quiet after that but still had a bit of whine.

1705170084582.jpeg


I lucked out on my Cougar, it must have a pump that came out of the factory with perfect tolerances. It has always been silent. I drain and fill the reservoir every so often with Mercon V to keep the fluid clean.
 
The 4.6 pumps are quieter than the 3.8 ones IME but I also don't recall the one on my 94 being super noisy - at least, not as noisy as I've heard from pumps on their way out!

It sounds like you've got the best combo of fluid at this point, but there's a certain amount of uncertainty with the age of both the rack and pump. Worn out ball joints and the size/config of the front tires also have an impact on steering feel, FWIW.

You could easily chase this deeper into the money pit. New rack, new pump, new ball joints, etc.

One other random tidbit - on my 98, I blamed the 200,000-mile-old PS pump for a whine noise that was, in reality, the alternator bearings going bad. I swapped out the OG pump for the takeoff pump from the OG motor I had in my 96. When the sound didn't go away I replaced it with a NOS pump before I had the sense to look elsewhere for the noise, which is when I realized it was the alternator. :facepalm:
 
The only pump I've heard make noise was the one I broke with the wrong fitting.
 
Yup. I used an an fitting that was too long, and rubbed the bump. My Mechanic, Walter told me all about it, lol. There is an instruction to grind it, I used a nylon gasket, and thought I was fine. I was Wrong, lol. Do it with the belt off, and if it's hard to spin, grind and try again.
 
I’ve just filled and turned to burn the system no vacuum there.
 
Last time I did a flush and fill, I jacked up the front end and just spun the wheels from lock to lock a few times to squeeze old fluid out of the rack (and after filling, fresh fluid in and air out). After giving it a couple minutes to "de bubble" I fired it up and did the same with the pump running, shut down, and repeated it one more time to fill the reservoir to full.
 
Last time I did a flush and fill, I jacked up the front end and just spun the wheels from lock to lock a few times to squeeze old fluid out of the rack (and after filling, fresh fluid in and air out). After giving it a couple minutes to "de bubble" I fired it up and did the same with the pump running, shut down, and repeated it one more time to fill the reservoir to full.
With the older style pumps they use on the v6 cars I do this too. And if time isn't a concern I've let them sit over night to help work the air out.
 
Speaking of instructions...
Has anyone ever done the vacuum pump procedure from the workshop manual?
If you can find a cap with the vacuum adapter it's a simple process.
 

Similar threads

Back
Top