Nissan Type A suspension fluid, need replacement

[VH45DE]

This is for a hydraulically assisted closed loop suspension system on a survivor Q45.

Some basics on the system for those unfamiliar:
It has a radial plunger engine driven pump, System pressures are typically 400 to 1450 psig.
It has a number of spool valve bodies solenoid controlled
It has strut actuators at the 4 wheel positions
it has 9 accumulators that have fluid on one side of the piston and trapped Argon (nitrogen was used for factory fill) on the other.

I posted a VOA of the factory Nissan Type-A suspension fluid here:Virgin Type-A
The Nissan fluid is no longer available in the USA.
Since this fluid is used in a 'hydraulic' system, I figured I'd post here as well.
The viscosity is light, close to an ISO32, but I'm not all that familiar with dedicated Hydraulic oils or what might have a similar additive pack to what the system was designed for.
Looking for input.

 

[Astro14]

My Mercedes has a hydraulic assisted active suspension. The OEM fluid is Pentosin CHF-11s. Synthetic oil base.

Here are the specs: http://www.pentosin.net/specsheets/Pentosin_CHF_11S.pdf

Exactly the same viscosity as your VOA from the Nissan fluid.

CHF-11s can be found in liter, 5 liter, or 20 liter jugs on Amazon, Rock Auto, or at local parts stores (my local foreign car parts store carries it, for about $19/liter). 5 liter jugs on Amazon bring it down to about $13/liter.

It's designed for suspensions, so detergency, viscosity, anti-foaming additives are all appropriate to your application.

Liquid Moly has a selection of suspension fluids, if you would like an alternative to the Pentosin.

https://products.liqui-moly.com/oil...23633-122929171.1558023633&trstate=0

 

[VH45DE]

Thanks Astro. So this is what you use in the S600?
It is interesting, because I've been looking at the CHF11S product as an alternative fill for power steering fluid on my A6 Avant.

I'm hopeful that you or someone would be able to post a link to some VOAs on these hydraulic fluids.

Off topic: have you had to recharge your accumulators? Have you met up with Keith Bowers?

 

[Astro14]

Sorry for the delayed response, we are out in Saint Louis for my daughter's medical school graduation.

Yes, I run the CHF-11s in the S600. I flush it every two years and Mercedes has a very good filter in the return line. The fluid is used for both the suspension system and the power steering system.

I don't have a VOA on it, but after about two years, the color (clear green) starts to fade a bit and I reckon it's about due for a change. The Mercedes STAR system allows me to "Rodeo" the car: run each suspension component through full articulation. I do this Rodeo while feeding pressurized* fresh fluid into the reservoir and catching the fluid in the return line in a waste container for a complete change and flush.

The valve blocks and other components in this system are subject to corrosion from moisture and degradation from debris (wear particles) in the fluid. Keeping the fluid clean helps preserve the life of some very expensive components.

I don't know what Infiniti has for flushing regimen, but I would recommend similar.


*The Mercedes suspension pump requires fluid under pressure to prime. It suctions fluid from the reservoir. I have a 2 gallon pressure pump made by Motive (like a big power bleeder) that I use exclusively for suspension fluid.

 

[VH45DE]

Originally Posted by Astro14
we are out in Saint Louis for my daughter's medical school graduation.

Yes, I run the CHF-11s in the S600. I flush it every two years and Mercedes has a very good filter in the return line. The fluid is used for both the suspension system and the power steering system.


Congrats to your daughter!

Filtration in the infiniti system also good. multi-stage, fine mesh in control valves and pleated paper also in return. Used sample had insolubles at 0.0 (would have expected nothing worse). I don't have rodeo mode (specialised nissan consult-i interface tool for the active ECU required)
curious if your system has separate pumps for PS and active? The infiniti system uses a tandem single shaft pump. the PS side is typical Dex iii recco.
funny you mention priming the the active pump. Infiniti recco's to vac the system after fluid fill to suck out the air bubbles. I once forgot to do that and of course had no pump head. fortunately an easy fix with my cooling system venturi vacuum.
I have also used the motive (dry) to pressurise cooling systems for leak checks.....good versatile tool.

 

[Astro14]

The pump for the S600 is a tandem pump. One pulley, two hydraulic chambers/circuits, two inlets, and two outlets. The fluid doesn't mix between PS and suspension.

I hadn't thought to vacuum the system to remove bubbles, but it makes sense. The Mercedes system has a total of 4 accumulators. They need replacing periodically. Pump noise is usually amoung the first symptoms.

Though my most recent pump noise has only gotten worse and I believe it's time for a pump. Not cheap. That's a project for next month...

By the way, I always liked the Q45. I always thought it was much more of a sports/muscle car than the Lexus competition. That active suspension must give it nice handling along with a plush ride.

 

[VH45DE]

Originally Posted by Astro14
The pump for the S600 is a tandem pump.

Though my most recent pump noise has only gotten worse and I believe it's time for a pump. Not cheap. That's a project for next month...

By the way, I always liked the Q45. I always thought it was much more of a sports/muscle car than the Lexus competition. That active suspension must give it nice handling along with a plush ride.

Thanks for the replies.
Good luck with your pump, at least it sounds like you have continued parts support which I have heard is a legacy of Mercedes. Parts obsolescence is becoming near-prohibitive for me. I have to get creative at times, but I'm also a stickler for maintaining true to the car's provenance.
I'm biased of course, but I've always thought the 1st gen Q45 is underappreciated for what it is. Of course, very mediocre compared to today's car's in every category, except I would offer....'soul'. 25+ years ago it was waaaaay ahead of its time. I actually own two examples of active Q.

 

[VH45DE]

PS- I got some Lubri-Moly central from Amazon, we will give it a go.

 

[nthach]

Supposedly the Nissan Active Suspension is based off Bosch or ZF designs - seeing how Bosch worked with Hitachi in the 1980s-1990s. I think Pentosin CHF 11S is a safe bet.