I just bought a 2003 SL55 AMG and am replacing the leaking front strut. I see that Mercedes recommends "MB Hydraulic Fluid" for the suspension, and Pentosin CHF-11S for power steering. But I see videos of replacing the suspension fluid and they use a Pentosin CHF-11S.
Does anyone know why MB specifies their fluid for suspension but not for power steering? Has anyone know about problems from using the Pentosin fluid for suspension?
MB doesn't manufacture their own fluids. Pentosin CHF-11S is what the "MB Hydraulic Fluid" bottle is filled with and is the correct fluid for the ABC system.
There are two other MB-spec'd hydraulic fluids in play:
-Power Steering (Dark Yellow Tint) - Factory fill for the PS system. CHF-11S can also be used in the PS system, and the fluids are interchangeable.
-Hydraulic Top (Light Yellow Tint) - Limited to only the retractable top system.
Congrats on the purchase of your 2003 SL55 AMG! It's a fantastic car. Regarding your question about fluid use, it can indeed be a bit confusing.
Mercedes-Benz specifies "MB Hydraulic Fluid" for their suspension systems because this fluid is specifically formulated to meet the unique requirements of the Active Body Control (ABC) hydraulic suspension system used in models like yours. This fluid is designed to maintain the proper viscosity and performance characteristics under a wider range of temperatures and pressures, ensuring optimal performance and longevity of the hydraulic components.
Pentosin CHF-11S is indeed used in power steering systems and has been a popular substitute among mechanics for various applications, including some suspension systems. Many users have successfully used it in the ABC system as well, but it’s essential to note that it's not an exact match for the MB Hydraulic Fluid. This could potentially lead to differential performance aspects in the long run, especially if the fluid properties differ significantly (like anti-wear additives, foaming tendencies, or thermal stability).
Make sure to keep an eye on the fluid levels and check for any signs of leaks or irregularities after your strut replacement.
OK. So it's clear why they call it artificial. But intelligent? Answers like this, like the theme of the topic, have me pondering substitute definitions.
Regarding your question about fluid use, it can indeed be a bit confusing.
No it's not. HLG answered the question succinctly.
But it’s essential to note that it's not an exact match for the MB Hydraulic Fluid
Yes it is. It is an exact match.
This could potentially lead to differential performance aspects in the long run.
No it won't, as they're the same fluid.
That AI-search result copy / paste was entertaining.
To make sure anyone reading this isn't distracted by misinformation, below is the data sheet for CHF-11S which:
-References the specs / approvals it meets for MB (345.0, also attached).
-Specifically links it to the part number of the "MB Genuine" hydraulic fluid.
"Pentosin CHF-11S" also happens to be printed on the "MB Genuine" bottle...so it's "essential to note" that they are one in the same.
Respectfully, this isn't a difference of opinion as you have a documented specification, a clear factory approval and the CHF 11S name literally printed on the MB Hydraulic Fluid bottle.
As for "MB insider information" to help settle the subject, here it is straight from WIS (factory service manual):
(Note the reference document numbers and how the MB Hydraulic Fluid and Pentosin CHF 11S products are bundled together).
HGL600, you are absolutely correct. I went to the Mercedes dealer to get some small parts, and while I was there I asked for the part number of Mercedes Hydraulic Oil (which are the words used in my operator's manual). He could not find the part in their parts list, so he looked up what was put in the car at the factory. It was Pentosin CHF 11S.
It is wierd that they did not put Pentosin in the Operator's Manual for ABC system, but did for the Power Steering Fluid.
HGL600, you are absolutely correct. I went to the Mercedes dealer to get some small parts, and while I was there I asked for the part number of Mercedes Hydraulic Oil (which are the words used in my operator's manual). He could not find the part in their parts list, so he looked up what was put in the car at the factory. It was Pentosin CHF 11S.
It is wierd that they did not put Pentosin in the Operator's Manual for ABC system, but did for the Power Steering Fluid.
It really is to blame here, as it not only creates confusion re: the ABC fluid, but is also (ironically) incorrect about the PS fluid as MB Power Steering Fluid was different from CHF 11S (from the factory).
What it should say is:
-ABC: MB Hydraulic Fluid (Pentosin CHF 11S)
-Power Steering: MB Power Steering Fluid (Can Be Substituted With Pentosin CHF 11S)
