jkowtko

Did you follow the refill directions? After you do the initial fill, run the engine for a few seconds so the pump will start pushing fluid into all the empty spaces. Stop it after a few seconds, put in more fluid. Make sure each time you fill fluid only to the bottom pair of markers on the dipstick ... those are the "cold fluid" levels. You may have to do this a couple of times to get the fluid to the right level. When you do this turn the steering wheel gently lock to lock to get fluid into the hydraulic chambers in the steering rack. After you've done this a few times and you think the level is good, drive the car around somewhere slowly and gently turn the steering wheel left to right, lock to lock, about 10 times. This will ensure that the steering rack chambers are filled with fluid and hopefully all of the air bubbles out of the system.

If you're hearing more sound now you're likely sucking air. If you can get it back to the state as before, then good, but unfortunately it sounds like not the fluid type or level, but some bearings that are going bad.

So you'll have to do the knife trick again, touch it to the PS pump body, the AC compressor body, and the end of the bolt (should not be moving) that is holding the tensioner pulley. You should feel the vibrations stronger on one of those than the other two.

Regardless if the fluid wasn't causing the problem, it is much better to have the correct fluid in the system ... it will prolong life of the steering rack as well as the pump. Incorrect fluid can wreck the pump over time as well as cause leaks in all the rubber seals.

DaODB

Just took it for a ride and the louder noise went away. I did the air draining by doing the on/off procedure and on a different forum (Infiniti) I read to lock it in the full radius for 3 seconds.

It's back to the normal sound, but I guess the bright side is the ride is much smoother and the turning is something I have never experienced since I bought this car 3 years ago!

An observation I made is that when idling at a stop light, I felt a very small (but noticeable) vibration.

My friend called me as I was under the car removing the splash guard saying that his car was having troubles and sounded sort of like mine and he replaced a belt and voila! Noise gone. However, he has a good ol GMC Jimmy.

I had a girl in my passenger just this Friday (while this has been the only thing on my mind) and explained to her what was on my mind. She was like "What sound? I don't hear anything." And was shocked I was even contemplating on paying $850 to get (whatever it is) fixed.

I will try to feel for the vibrations again and possibly go to the mechanic. I definitely do not want to shell out the money for a Steering Pump and that not be the problem. I may travel far this weekend, though, but he seemed to be sure that nothing terrible will happen if I drive the car around. I guess I'll just have to put this at the back of my mind and just turn up my radio louder, lol.

Thank you very much!!

EDIT: To be honest, I want to say it was the belt tensioner causing the most vibrations. Out of the 3, the power steering pump seemed to cause the least vibration, and it was a close one between the tensioner and the compressor. I kept comparing them, but I feel the tensioner was indeed causing the most vibrations.

jkowtko

Glad to hear your steering feels better! Getting the right fluid and fresh fluid is key on these vehicles ... I experienced the same.

If you haven't already done so, give the fluid level one last check when it's at full temp (engine having been run for a half hour) and read the level which should be between the two upper marks on the dipstick.

How much fluid did you use? If you still have half a quart left I suggest you do this again after a week just to get out the last traces of the old fluid. Even if you have less than but close to half a quart, do it again but when you drain keep some of the "old" fluid so you can top off the system if needed. Then you'll be good for a few years.

Regarding vibrations, I would think you want to replace the bad bearing before it goes out and causes some real damage to your engine and leaves you stranded somewhere.

Check the DIYs on removing the serpentine belt. As someone else mentioned, don't remove it (unless it's looking old and cracked -- then replace it), but just relieve the tension so you can spin the pulley by hand on the tensioner, and turn the pulleys on the PS and AC to see if they have a rough feel. If the tensioner pulley is bad you may be able to buy and replace just the pulley for $50 (or the entire tensioner for $100+) ... you'll need to look for DIYs on this as I don't have this engine and have never done this before. (my belt tensioner broke but on my engine it required removing the kompressor to get the tensioner bolts out ... $$$).

If you think this is a separate issue, I suggest you start a new thread, since this thread should remain focused on PS fluid changes. Come to think of it, now that you've ruled out PS fluid from causing the bearing noise, you might want to start a new thread for the noise as well. A new thread with a relevant title will make it easier for others with similar problems to find these discussions on the forum.

mleskovar

Out of curiosity.....are you checking the fluid level with the motor off ?

jkowtko

Just a note -- I don't think this step is needed. The fluid in the reservoir will drain out the bottom hose when you disconnect the hose. I just did another drain and fill to use up the last of the fluid I had left, and I got out a little over half a quart just from disconnecting the bottom hose.

I would also suggest doing this service while the fluid is warm -- the fluid will flow better and you should get more out.

kluvsbenz

I have a 125 buck off coupon so I was going to use it for this power steering service and rear differential service. Now 2 of them in North NJ don't even offer the power steering service. Couldn't believe it Now for the rear diff. service, big disparity in pricing. One wanted 95 bucks to do it. The other offered 220 bucks. Again Trying to figure out how I can use this coupy before the end of the year.

jkowtko

My guess is that the $95 service is using cheap gear oil (< $10/qt) that may cause you problems over the long run, vs Mercedes spec oil (~$30/qt). The diff uses a little more than a quart so two quarts are needed.

If you want to do the diff yourself, it's $60 for the Mercedes gear oil and $10 or less for the inexpensive fluid pump. For tools that you can use again -- $50 for a pair of ramps and $15 for the 14mm hex bit socket.

kluvsbenz

DIY!Have plenty of excuses for ya My driveway is on an incline, my garage is tight, It's cold in the poconos right now, I'm lazy, etc. Hey I only recently DIY changed my oil and changed spark plugs, air filter. Now you trying to get me even more dirtySeriously, I want little projects like these done by a stealer when I get these coupys. If possible, anyway. Times like these, I wish I knew somebody with a lift.

jkowtko

If you're going to pay for it, my only suggestion is to make sure it's done with the correct fluid. The diff oil will be need to be changed only once in a blue moon, so no sense in setting yourself up for a $1000+ differential repair vs an extra $50 for the correct gear oil.

If the cheaper Indy will let you bring in the gear oil and they just charge you the labor, then you can assure you have the right fluid. Same for PS.

kluvsbenz

^^^ For the PS fluid, what the OP prescribed on the first page of this thread do? In other words, is the fluid the same for all W203's? Particularly my model 06 C350 Sport-M272 engine.

kluvsbenz

Searched on Autohausaz and they had the same PS fluid-Pentosin for $19.87

kluvsbenz

Hate to beat this dead horse but I had the diff. oil changed once at 60k. Now I am at 107k so I was thinking it was time. The PS fluid I never had changed so that's why I wanted that done pronto!!

jkowtko

I paid $20 for Pentosin, and $30/qt for Mercedes gear oil.

For the PS fluid you need only one quart ... you'll use maybe 3/4 for a drain and fill. If you've never had the PS fluid changed in 100k miles you should notice a signficant difference in feel of the steering afterwards. If it were me I would buy two quarts and do a second change in another couple of months, to get out as much of the old fluid clinging to the nooks and crannies. Then do it once every 2-3 years afterwards.

KHARBAT1

So , do we change the power steering oil or is it life time ? Thank you .

jkowtko

I don't think any of the fluids on the car are "lifetime" ... the US tried on the transmission fluid but backed off later.

For PS fluid I would suggest 2-3 year intervals if you want to keep the steering feeling fresh and new, and avoid excessive wear resulting in future problems with the PS pump and rack.

Even if you use a mechanic to do the work, you can check it yourself by sucking a small amount of fluid out of the reservoir into a piece of clear tubing and checking it's color. It should be clear with a light green tint. If it's the least bit clouded or amber in color, it's getting old and ready for a change.

Fyi, you don't need to discard the fluid when you check it -- just suck it up several inches into the tube like you would milk in a straw, put your finger over the tube opening to hold the fluid in the tube so you can get a good look at the color, then take your finger off the end of the tube and let the fluid flow back down into the reservoir. A simple way to check.

VVF

Wow... flushed mine today. 126k miles, seems like it's never been changed. Dark reddish-brown color with a hint of bunt smell?
Then used HF 1.5 ton jack to lift the front and turned the steering wheel lock to lock about 40 times, topping off the fluid.
Then started the car, waited for 1 min and turned lock to lock 10 more times and had to top off some more (!)

Thanks for the DIY!

VVF

Hmm, now it squeaks when I am turning the wheel to the left the last half-turn, driving very slowly or standing.
(before the flush, it was squeaking only when I hit a wheel lock on either side)

The hot fluid level is on the '80 Max'. I take squeaking means there is air in the system?
Do you guys have ideas on how to get rid of that air?

jkowtko

What fluid did you use?

KHARBAT1

Is it a must to go under the car and disconnect the hose and drain from the plug ?
No question that you will end up with a better job . However , would it serve same purpose if you extract the ps oil , then refill ? I am trying to avoid stirring things up that could end up leaking .

jkowtko

It's a matter of how many iterations of drain-and-fill you will need to do to get the fluid sufficiently fresh and new (green and clear).

Bottom draining gets more fluid out than just siphoning from the reservoir. I've done both and I will always do the bottom drain from now on. That bottom hose is a low-pressure return hose so any hose clamp at medium tightness will hold and seal it tightly. I now have an inexpensive screw type hose clamp on the bottom so future fluid changes will be relatively easy.

VVF

I used Pentosin CHF11S, the green one.
It only squeaks when turning the wheel left. Right seems ok

jkowtko

Hmmm ... this may be beyond my level of knowledge then.

However if you made the change from very old fluid to new, and the noise characteristics changed as a result of the fluid flush, then the system could be in the process of "getting used to" the new fluid.

As I have learned from my car -- and with advice from Glyn -- the rubber components in the system will react negatively from old or incorrect fluid. Replacing with fresh correct fluid will immediately change the fluid characteristics of what's running through your system, but it will take a while for the rubber seals to regain their original (and correct) form. On my car it took several months for the PS shudder to disappear. So if your noises are seal-related and not drive belt slippage, maybe this will go away over time.

And if your fluid was that bad, how well did you flush? If you used only one quart and 1-2 partial flushes, you should consider doing this again in another month or two once the residue in your system has worked loose and is mixed in with the new fluid. IMHO the PS systems on these cars are very sensitive to the fluid.

Btw, how is the steering now vs before? Feel any better? smoother? less effort?

VVF

Yes, I am hoping for that Today it seemed better - less noise.
Does your car make a squeak when you hit a lock on either side though? I read somewhere that this is "normal" because the pump is going nuts in that situation.

I filled the reservoir and waited until the fluid draining from the hose below became mostly green in color. I think I would've used the whole can of pentosin and not gotten it to be absolutely pure because there would still have been some traces of the old fluid inside the system.
Feels like it's a little bit lighter, especially when you turn it rapidly.
Actually I also feel some shudder in the steering wheel when I am turning the wheel slowly whilst standing or moving at very slow speeds. This shudder I had before the flush too.
But we'll see how it progresses. If the squeak goes away I am totally fine

jkowtko

Okay, sounds like you've done a decent job at the drain and fill. I would still consider doing this again in a month or so.

I'd give the noises at least a few weeks to simmer down ... then please report back

As for hitting the steering rack end hard -- yes I wouldn't be surprised if you hear complaining noises when you do that. You're basically telling the hydraulic system to push in a direction that it can't budge. I wouldn't do that as a habit ...

However, in order to help get the last bit of old fluid out of those steering rack hydraulic chambers, it wouldn't hurt to *gently* turn the wheel to the rack end when making turns at slow speeds, as in pulling in or out of a parking space.

VVF

Lol, I wasn't actually hitting it 'hard', just hitting as in "reaching the stop", like "hit a roadblock" or whatever.

Anyways, the squeal is gone now (the brief squeak at full lock is still there).
Some light shudder remains, but I haven't driven the car that much, kinda just commuting.

I did feel a definite improvement on the freeway though! Feels lighter, plus I can drive straight without holding the steering wheel (used to slowly drift to the right, even after an alignment).

One thing that I'm curious about is what kinda fluid was there before... It's really hard to believe that Pentosin changes color so much. I think it might have been ATF, but the manual says Pentosin...
Has anyone changed the fluid for the second time yet, what color was the 'old' one?