Power Steering Noise - Foamy Fluid

[skibo]

I've searched the forum and can't find anything like this symptom - hoping someone has seen something similar.

Driving on the interestate Friday night - got off at an exit and heard a loud groaning when I turned the wheels. Got louder the more I turned - didn't matter if the car was moving or not. Sounded like low fluid.

Saturday AM checked fluid level - just right. The noise was gone until it returned after after around 1 hour of in-town driving (reported by wife).

Sunday - noise is back after 1 hour of driving. Open steering reservoir to find the fluid is all foamy and under pressure when I opened the cap.

Thoughts? I have the weeping around the hose clamp, but the level was OK. It's possible that my local shop added some steering fluid of an incorrect type when the car was inspected 3 weeks ago, but why no symptoms until now?

Any input appreciated.

[PaperToast]

did some looking on volvospeed and this is what i found to be possible causes.

1. you have different PS fluids in there. :(

2. theres a leak allowing air to get in the system.:mad:
3. bad PS pump.[cussing]

first thing to do would be to change the fluid. quote "If the fluid is reddish, use ATF. If light green or more amber, use CHF-11S."

for the air problem i read that if you run the car with the reservoir cap off for a few min that allows the air to escape.

the other prob, well thats an easy one fo figure out.

[BillAileo]

The OEM fluid for these cars is Pentosin CHF-11S which is a special synthetic low foaming hydraulic oil.

[skibo]

Hmmmm. Thanks for input thus far.

I see in a couple of the posted 'Vadis' excerpts that the proper 'cold' fluid level is 1/2 way between the 'full cold' and 'full hot' lines on the dip stick. I was definitely at the 'full cold' line. May add some fluid (if I can find the right stuff tonight) and check suction hose.

[BillAileo]

Pentosin CHF-11S may be hard to find on a local shelf. I got mine from the local NAPA store but they had to order it in. Fortunately that only took one day.

[skibo]

I found the Pentosin on the shelf at the only foreign car parts place in town - US$30. Sucked out what I could of the old, dark fluid and filled the reservoir with the beautiful green stuff. Cold fluid level had been at 'full cold', but based upon some of the VADIS postings I found here, I filled it to a little above the half-way point between 'full hot' and 'full cold'. Problem seems to be solved. I think I was just sucking air due to marginal fluid height which was foaming the fluid after some period of time - especially on the highway when the circulation rate is probably higher than around town due to consistantly higher engine speed.

So, my take-away is to beware of the markings on the dip stick - seems like even Volvo recognizes that they are incorrect, based upon comments in the maintenance instructions.

[bhhardy]

Skibo -

How is your situation? I am having this same problem.

We topped off the fluid reservoir to nearly the hot line on the dip stick, and tried to bleed out any air by turning the wheel left and right repeatedly, but the situation persists, and gets worse as the engine reaches operating temperature.

I saw this from Tech, an administrator on VolvoForums:

"The bottle itself might be bad. Remove the cap and look inside the bottle. With a flashlight look inside where the little hose attaches at the top. There should be a plastic tube from there to the bottom of the bottle. Sometimes that fall off. Then when the car warms up the fluid will airate and cause a noise."
(http://volvoforums.com/forum/showthread.php?t=26391)

I looked inside ours and I can see a little hose sticking out very near the fluid level line, about 2 inches. Does this sound right? It doesn't seem to match Tech's description, but I can't really figure out what he means. Should it go all the way to the bottom? Could that be sucking air?

Thanks for any help on this!

Barbara
----------------
'01 XC70

[skibo]

Barbara -

The problem is better, but still there - the longer the car is driven the louder the noise and foamier the fluid. I'll take a look at this tube you describe this weekend (when I have access to the car in the daylight) and report what I see . I vaguely recall seeing a small tube sticking out of the side within the reservoir - where the fluid is returned - it looked like it was made of copper - maybe there is a hose that is supposed to slip over that to 'deposit' the fluid at the bottom rather than squirting at the top. I can see where that might stir it up over time.

Fingers crossed.

[skibo]

Well, I looked at it this weekend, and found that this 'displaced tube' was the heart of my problem all along. At the inlet port, there is a metal insert that extends about 1 inch into the reservoir. A plastic tube with a right-angle bend snaps onto the metal tube and directs the returned fluid to the bottom of the reservoir. Without it, I think the return fluid stirs up the surface of the fluid and causes it to foam over time.

I took the reservoir off and drained it so that I could better see what was happening in there. The tube just snaps into place, and it looks like it may have been captive at one time against the far wall of the reservoir, but the sides of the reservoir seem to have bulged out over time and now it is much less secure. I snapped it back into place, but expect that it will come off again at some point.

I considered replacing this tube with a rubber hose or something, but the old tube would not come out without destroying it, and the metal insert is so smooth I think a hose would eventually come off and possibly block the suction port (which would be really bad). Along similar lines, I considered a drop of glue, but again, had visions of a shard of glue coming off and finding its way to some orafice or delicate rubber seal in the rack.

Thanks so much for the tip BHHARDY! I was preparing myself for a new pump or rack. I'm surprised I never saw mention of this before on the forum.

[Aviator]

Excellent sleuthing there Skibo!! Good to hear you found something wrong (well, not good, but you know what I mean).
Dave.

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