Power Steering Noise when Hot

mbaskette · Post by **mbaskette** » 30 Nov 2016, 07:06

My 2000 V70 XC has been producing power steering noise with the following symptoms:

1) Steering seems to be fine in that there is no noticeable loss of power assist
2) System makes no noise from cold start, but after about 20-25 minutes into my daily commute it groans when steering left/right once the system is hot.
3) Fluid level is fine with no visible leaks under the hood and no fluid on the driveway.
4) Level of sound is proportional to the load on the system. Slow speeds, sharp turns means more noise volume.

Suspecting the pump, or an over pressure situation from somewhere else in the system. Anything easy to check other than the fluid level, before focusing on the pump?

Thanks
Mike

Post by **abscate** » 30 Nov 2016, 07:35

Now that Thanksgiving is over, use your turkey baster and remove the PS fluid and replace with fresh.

Check your manual for the right fluid - Volvo transitioned from PS fluid to Pentosin around your model year.

Post by **shiloh51933** » 30 Nov 2016, 10:33

[quote="mbaskette"]My 2000 V70 XC has been producing power steering noise with the following symptoms:

1) Steering seems to be fine in that there is no noticeable loss of power assist
2) System makes no noise from cold start, but after about 20-25 minutes into my daily commute it groans when steering left/right once the system is hot.
3) Fluid level is fine with no visible leaks under the hood and no fluid on the driveway.
4) Level of sound is proportional to the load on the system. Slow speeds, sharp turns means more noise volume.

Suspecting the pump, or an over pressure situation from somewhere else in the system. Anything easy to check other than the fluid level, before focusing on the pump?

If it's making a growling sound I'd say the bearings for pump are on there way out. Check the tension on the belt, if it's way too tight it can cause bearing failure for the pulleys.

Post by **oragex** » 30 Nov 2016, 12:07

I had such noise. When the engine gets warm, the screw on the hose clamp was getting loose allowing some air to be sucked in. Pass a finger under the clamps at the pump and reservoir.

mbaskette · Post by **mbaskette** » 01 Dec 2016, 06:30

Thanks for all the responses...

I got the car in August, prior owner had recently changed the reservoir...

Hose clamps are all fine. Owners manual shows "ATF" as the proper fluid. Checking the reservoir I find 2 things. 1st, fluid level with a cold engine was above the hot fill line. I've fixed that, but groan/whiring sound persists with hot engine. 2) The fluid is a clear/brownish (possibly scorched, sorta smells that way). Definitely not red.

I see Pentosin mentioned in this thread and other power steering threads. I ask Pentosin what? Pentosin is a brand name, not a single product or chemical. Hydraulic fluid? Transmission Fluid?

Post by **regent** » 01 Dec 2016, 08:07

Your car will most likely take Pentosin CHF 11S, you can check here: http://www.pentosin.net/f_hydraulicfluid.asp

Post by **regent** » 01 Dec 2016, 08:14

On another note, I did have a somewhat noisy PS pump, which I replaced along with the suction hose just a few weeks ago. Once the 'clackety-clack' PS noise was gone, I was then able to hear another noise from a failing alternator clutch pulley that made my car sound like a diesel...
With the alt replaced, everything is normal - happy camper.

If you are to change your pump, make sure you put in a new o-ring on the output pressure line.

mbaskette · Post by **mbaskette** » 30 Dec 2016, 13:27

OK... Got some garage time over this holiday break. A-B-A swap of the power steering pump with another unit (used), new fluid at proper level, hose clamps to the pump are tight... again, no leaks to be seen. Both pumps groan when the car gets to temperature. Since starting this thread I can say that on a really cold day it will not do it at all. On a warmer day it will do it sooner. Definitely a temperature component to the issue. Odds of both pumps having the same issue is possible I suppose, but seems unlikely to me.

Post by **abscate** » 30 Dec 2016, 18:23

i have a third one you can try if you are a glutton for punishment. Sounds like a rack problem - the steering rack, not the punishment rack - although Ive heard the punishment rack is preferable to having to work on the steering rack...

mbaskette · Post by **mbaskette** » 03 Jan 2017, 17:45

Success... finally! Bad power steering reservoir. The internal pipe that connects to the small line at the top of the reservoir had separated off the brass tube and was rattling free inside the tank. I assume this allowed the system to gulp air and/or foam easily when the fluid heated up. New reservoir, pump groans fixed.