I have reviewed my 300E owner's manual and can not find any discussion on checking the power steering fluid (oil) level. The first thing in the morning I have noticed a sound when turning out of the drive. The sound is like I have experienced with American cars in the past when the fluid level is low. Checking the brochure of factory approved service products the only source of power steering oil appears to be the dealer. Does MBZ use a different fluid/oil than other cars? Is the can at the front of the engine with the black plastic knob in the center of the top for the power steering oil? Any suggestions about the procedure to check the power steering fluid level?

That sounds like the power steering resevoir. Should look about the size of a small coffee can. Unscrew the knob and lift off the top. There is a line stamped in the body, about 1/2 inch below the rim, that's the fill line, the filter should be under the plate with holes in it at the bottom. Any quality power steering fluid will work.

though expensive, i'd recommend MB fluid.

My '90 300SE groans a little when I turn right for about a second. I looked at the fill reservoir and it was about 1/2" from the top. I put a little more in, but it still groans.

Does this sound like a pump going bad?

Crowe
 

You found it alright, that little black knob. And the M/B suggested products only list M/B Fluid. My '87 W124030 has 170,600 miles and has had no steering gear or pump problems. A little trick I use is as I change my oil from the Top Side with my El Cheapo Oil pump, I remove the P/S pump oil filter and using my pump I suck the resevior empty and refill it with Valvoline Synthetic P/S fluid. I do this ever 3500-4000 miles. I also do something similar to the transmission. Overkill? Oils Cheap, Pumps and Gears ain't. As for noise, the power steering pump at end lock can produce up to 1000psi, noise will be heard. This is for the cirulating nut steering gear, not Rack & pinion which is another topic for discussion.

Happy Trails Beep Beep from Houston.

Donald
AJ likes Vavaleen

Just checked the power steering fluid level and found that it was at the top of the plate above the P/S filter. That leaves approximately 3-4 inches up to the top of resevoir empty. I did not see a fill line on the resevoir, but expect that the fluid/oil level has got to be higher. Someone mentioned that the fill level would be up to 1/2 inch of the top. Is that level correct?

I am attending a MBCA Peachtree Section meeting at a local MBZ dealer in the morning, so I will purchase some MB power steering oil and take care of the problem.

Crowe
 

You're doing the right thing in attending those training sessions. For then you will get it like it is, not he said or I heard not I do and and he doesn't . I wish you well and hope you get more involved with your machine for that's where the joy is, mono e mono, one to one.
Happy Trails Beep Beep from here to help Houston.
Donald

Crowe,

Your fluid is big time low. Once you start up, it'll drop even lower as the fluid starts moving. I say it will drop lower, because as low as it is, you've likely got air in the system. Best part is, it will self bleed, just give it time. Fill it up, and let it idle for a while, then slowly turn the wheel stop to stop, afterwards check level again and top off.

Next, for the level to get that low, you probably have a leak in the system. Notice any oily puddles on the garage floor lately? Could be a leak in the hoses, front seal of the pump or from the steering box, or it's just never been checked. Until you verify you do or do not have a leak, I would check every other day to gauge usage, and top off as necessary.

Power steering pump
 

I use the Slick 50 Power Steering fluid, I had Mazda van that the Power Steering Pump squealed all the time, instead of changing it out I replaced the fluid with Slick 50 and it Stopped. Saved about $200

Thanks everyone!
 

I did notice some oil on the garage floor following the last oil change. I have always had a few drops on the floor but this was more than usual. I think that the person at the shop must have checked the power steering reservoir and did not retighten the lid properly. What I thought was oil must have been P/S oil/fluid. The side of the reservoir looked like it had a oil stain down the side, and the puddle on the floor was on that side of the engine. By the way, I was surprised to see that the "fluid" was black, not clear or red like other standard P/S fluid. Is this just unique to Mercedes?

Crowe,

I have a small p/s leak -- likely a high pressure hose and the "drips" are clear. I just topped of the resevior with MB fluid.

Shouldn't be black unless it's mixing with oil or grime before it hits the floor. Perhaps cleaning up the engine and re-checking will narrow down the culprit.

Best,

Did MB change their pumps? For my W116 the manual says use ATF. For my '99 VW, the manual says use a special mineral hydraulic oil. When I bought my W116 in October I checked all the fluids and the fluid that was in the steering pump was not red like ATF, it was more of a gold color. The pump doesn't leak, nor is there any steering pump noise. Just as a percaution should I some how flush out the system and put in ATF?

Slight correction on color
 

I should say the P/S fluid (for W126) is not clear per se, but yes, a more yellowish color. It does not look like oil, nor is it as red as say Dextron III. :)

Power Steering Oil/Steering Gear Lubricant
 

Just got back from the MBZ Dealer and purchased a quart of Mercedes-Benz P/S oil. It is a yellow-gold color and quite expensive. In fact, the parts guy suggested that I might want to use Dextron III. I will keep an eye on the oil level to make sure there is not a leak.

Even though on many models you can use ATF in the steering, I still use steering fluid. It may cost a little more but there have been suggestions that the detergents etc in current ATF composition can harm the pump and/or steering box seals. Plus as an added benefit, when you have drips on the deck, it's easier to tell at a glance what is leaking. If your fluid had gotten black, you definitely need to change your steering fluid and filter.