W211 Steering Fluid Replacement Interval
 

On my other MB's, steering fluid has always been kept clean. My simple regimen was just to drain and fill the reservoir every 10k miles or so and, if accessible, replace the filter every 60k or so.

Any recommendation as to what do with the CDI? The fluid is pricey...around $20 a quart.

The PO says he flushed it at least once a year. Overkill.

You need the service sheet for your year.

On my 2009, its never replaced. Level IS checked every 10k and topped off such that it is always at max.

Where can I access that? Is it accessible on the service CD?

My recommendation is to flush (not just drain/refill the reservoir) the P/S system when the transmission and differential oils are due to be changed (5yr/60Kmi max) with the Pentosin CHF-11S (or equivalent) P/S fluid.

The Pentosin CHF-11S Synthetic P/S fluid is the only replacement fluid recommended by MBUSA (the cars were originally shipped with non-synthetic fluid).


W211 Power Steering Fluid Flush.pdf - BenzWorld.org


Part numbers:
Q1460001 (light yellow, non-synthetic)
Q1320001 Pentosin CHF-11S (green, synthetic) MBUSA recommended (TSB: P-B-46.00/44 46)

On all my cars, I change the fluid and filter(if there is one) upon purchase and then every 2 years/24,000 mi.

Just to keep things in perspective, I bought a 1980 240D last March. The power steering system operated perfectly, reservoir was at the F mark, with no leaks but when changing fluids/filters, I removed a 3 piece filter assembly from the reservoir. Mercedes went to a 1 piece type filter in the early 80's, so it was likely the original.
Don

Does a W211 have a power steering filter? I didn't think they did, but if they do, someone show us where it is! Wouldn't mind doing mine because I doubt its been done before.

I don't think so. Or, if it exists, it's part of the pump internals and can't be replaced without considerable difficulty.

I've always been curious as to why MB moved away from the user-replaceable steering filter. Seems like such a good idea. As it's easy enough to design, I can only conclude that they no longer believe it to be necessary.

I agree, and PS filters always make for a good, "get me to the free shipping minimum" item!

For what its worth I just called NAPA - CHF11S in the Pentosin bottle is $19.99, $18 with the loyalty card. Called the dealer $25.20. So it looks like I'm going NAPA. Sometimes the dealer can beat NAPA on "exotic" fluids, or its the same price, and for the same price I like to think I'm fancy with the Silver and Blue bottle, but for like $7/qt I'll buy it in the generic bottle.

google found it. 2006 w211 Service Sheet - Documents

the filter for the powersteering is now incorporated into the black plastic reservoir mounted on the pump. You have to replace the tank to change the filter (like when changing the rack or worn pump)

the recommendation is to fill the reservoir with fluid and let it soak for about 15 minutes to prevent hydraulic blowout.

When I changed my ATF, I also used my mityvac and pumped out the PS tank. Refilled with Pentosin fluid, ran engine a bit, re-vacuumed and refilled. Easy job! Wouldn't think it needs to be done more frequently then ATF change schedule every 40-50k.

Is it fair to assume that, as long as the fluid is kept clean, there should never be a need to replace that filter?