EXACT Hydraulic Fluid for 6.9 Suspension

[cdw904]

Gents,

Thanks for your patience with me as I am new to the W116 (6.9) MB.  I attempt to search w116.org before I post just to ensure I'm not littering the site. So far, this has been the #1 place for me to learn about this rare vehicle and I look forward to contributing to the information pool as I gain knowledge as well -- your input is VERY appreciated so far.

My question today is about the EXACT type of Hydraulic Fluid for 6.9 Suspension:

I've scoured forums, websites, parts stores, etc. in search of a definitive answer on exactly which hydraulic fluid I should use for my hydropneumatic suspension system on my 1980 450SEL 6.9.  I can't find a 100% certain answer on what type of fluid I need to use.

I *suspect* I might need either

P/N: 000989910310 Genuine Mercedes
Cross References:
•   W0133-1635777
•   W01331635777

OR

P/N: 0009899103 Febi
Cross References:
•   0009899103A
•   02615
•   54340394395
•   W0133-1635777
•   MB FLUID
•   HF1
•   PFS32
•   MBFLUID


This data came from Autohauz AZ.

Does anyone know where I can find the Mercedes-Benz fluid part number?  In an EPC or maintenance manual?

Thanks in advance!

[daantjie]

Febi ZH-M Fluid is what you want to use. 
I run a thicker oil in my system, Shell Tellus S2 AW32.  As long as you stick with a mineral hydraulic oil of a reputable company, and have the right viscosity then you'll be in good shape.  The ZH-M fluid is very thin, like water, and approx 15W which is very thin.  If you have warmer ambient you can easily run AW22 or AW32 or perhaps even AW46 grade if you live in desert type climate where it routinely gets +40C.  Whatever you do do not run ATF in the system   I have seen many a HPF system ruined by ATF being run by either clueless or cheap owners.

[ptashek]

I'm using Liqui Moly Central Hydraulic Oil 2300 in my W124, but it can be used in any MB with hydro struts.
It was specifically designed for Mercedes-Benz hydro-suspensions, new and old.

The "genuine" oil you get from the dealership is just re-packaged Castrol Hyspin ZH-M, and is the only one with their official approval.

[s class]

I'm not disagreeing with the other posters, but I only use genuine Mercedes ZH-M.  Here in South Africa, a litre costs me only the equivalent of US$15, and it gets delivered to my door.  I usually buy a dozen at a time. 

[cdw904]

Thanks, gents! And thank you for confirming my suspicions about viscosity vs ride damping, Daantjie. I understood how the accumulators would represent the spring in the system but I wasn't sure about the "damping."

I'm enjoying learning about suspension system on this fine auto. I've actually started the vehicle, installed suction cups at each corner of the vehicle exactly 30 inches off the floor. So far, one week and 3 days later, the vehicle has dropped 1/16" only. I hope that is an indication that the seals in the hydraulic struts are in good condition!