I have finally joined the boiled power steering fluid club. I know that part of my problem was because I stopped with a hot car to take tire temps. I was able to get 2 cool down laps afterwards but things were very hot when I stopped (smoking brakes etc..)
At any rate, when I pulled into the pits, I opened my hood like I always do to let the heat out and the ps fluild was literally boiling!! It continued to bubble for about a minute. It was a cool day and I was driving my car the same as I always do in the same length session so I'm not sure how I've avoided the situation for so long.
I'll try some redline fluid next and if that doesn't work, I'll try the nismo cooler.

 

I "joined the club" in September when the weather got cool(?). I haven't had the overflow issue but did see the fluid percolating in the reservoir. Knowing that some people here have had success with the Redline ATF replacement I went that route first.

Changeout is simple. Pull the plastic tray that shields the steering rack and pinch/slide the spring clamp on the return line away from the fitting. Pull the hose off the barb and the pump/reservoir will gravity drain. Crank the steering wheel lock to lock a few times to drain the rack, not too fast or you'll make a mess. Replace the hose, clamp, and tray, and you're ready to refill.

Fill the reservoir then start the car and watch it disappear into the system, add fluid back to the fill line as necessary and crank the wheel back & forth to purge any air from the system. Note that the pump is noisy and the fluid foamy - THAT is cavitation. The condition you see at the track is different, no noise and no foam. I'm sure the fluid isn't reaching the boiling point (something like 275F - would melt the reservoir), but the combination of heat and high revs/pump speed seem to produce "big" air bubbles that burp in the reservoir. I don't know what to call it besides cavitation, but it's milder than the noisy "air sucking" condition you typically hear in a cavitating centrifugal pump. I bet underdriving the pump would help here, but hurt you in a parking lot.

Anyway, the Redline fluid made no difference whatsoever and the condition still exists. I've never dumped any fluid out the reservoir and never had any steering problems on the track - I'm going to cross my fingers and ignore it until one of those conditions pop up.

 

How much fluid is needed for a full flush?

Does the car have to be running when you are turning the wheel back and forth while draining?

thanks for the write up.

Dave

 

System capacity is about 3 pints and the car doesn't need to be running when you cycle the rack to drain it. You can do the job in about an hour. It's probably good for the system to change out the fluid once in a while, but the exercise didn't cure the condition for me.

 

So, two weeks ago at an event that had highs in the mid/high 50's, I found power steering fluid splattered on the underside of my hood. I don't know how it gets all over the place like that, especially since there is a lid. But, it didn't have any negative effects to steering.

I'm thinking of just ignoring the "problem", and clean up the mess from time to time.

 

yeah, Ive got splatter

 

FYI: you can use any automatic transmission cooler for the PS cooler.

i got my hayden #401 @ kragen.
worked great at the track!!!

 

That's good to know. Thanks Cheston!

 

I just re-read this entire post, and I still do not see any reason to add additional cooling for the PS fluid. I believe I was the only one to actually MEASURE the fluid temp. Just because there are bubbles in the fluid does NOT mean the fluid is boiling! Cavitation will cause bubbles, which I believe is what is happening to SOME drivers. Why it happens to some drivers & not others is still a mystery to me.

I'm more concerned about the diff fluid spewing from my diff breather! But, I have a solution for that!

 

my fluid is definitely boiling, not bubbling.

 

Why it happens to some drivers & not others is still a mystery to me.

Could it be that some run very near redline and others try to stay away from redline and closer to peak torque at 4000-4500 ? PS pump is driven by the engine, so the faster engine RPM, the faster the pump is turning. Just a thought.

 

The group of us that I measured the PS temps all run to redline, and all of us are fast. Well, the other 3 guys are VERY fast. And none of us have had an issue with boiling PS fluid.

Just because the fluid is hot and bubbly, does not mean it's boiling. ihatethatbobbarker, did you measure your PS fluid temp?

 

Your theory is interesting, and since you're the only one who has actually taken temps, perhaps you're on to something.
Where did you measure the temps? In the reservoir? Do you think the temp could be hotter in the acutal pump area?
When I opened my hood, the fluid looked like it was at a rolling boil, and it was coming up from the area below the reservoir. The bubbles were much more than I picture cavitation would cause.

 

I'd like folks to chime in who have upgraded their power steering cooler and still have this problem. If it got rid of the problem, I think it's suffices to say that the fluid is overheating. Both Enthuz and Daveh have very good points, but if bumping up cooling capacity fixes it, then there lies the solution.

Has anyone ever lost steering due to this problem, whether it be this car or some other make?

 

[QUOTE=daveh]
Where did you measure the temps? In the reservoir? Do you think the temp could be hotter in the acutal pump area?
QUOTE]

I measured at the reservoir with an infrared pyrometer. I'm sure the temps are higher at the pump, but I doubt but much.....heat rises. Since I did my measurements last May, I've rechecked the temp a few more times on much hotter days, and I still never saw temps over 180 degrees F. With PS fluid boiling point well over 300 degrees F, I do not believe it is boiling. I'm still using the OEM PS fluid, with about 35.000 miles on it.

I'm guessing that the larger capacity of the PS coolers allow the fluid to de-cavitate.

 

I used to have fluid splatter on the top of my hood after HPDE events. I then upgraded to the Nismo PS cooler and Redline PS fluid at the same time. I don't have splatter anymore. I have no hard evidence what fixed the problem (changed a lot at one time), but I did in fact have a problem.

And no I never noticed anything wrong with the steering, just noticed the splatter on the top of the hood.

 

I was told by the shop were I purchased my Redline fluid that the Corvettes were having PS failures at the local track. Several of them changed to the Redline fluid and it apparently solved their problem. It was recent Corvettes as the PS was covered under warranty. They just did not like ending the track day early because of the failed PS and having to go to the dealer for warranty...

 

I have the splatter, and my steering response completely vanished, turn the wheel, wait, ok now its turning, its kinda hard to describe, but it did not work well at all.
my hand told me it was burning hot... im sorry I didnt use a thermometer.

 

how much do PS coolers run

 

120 at Perfromance Nissan. I have had mine for a year and a half and run those 105 degree days with no problems.