MS-5931 is a power steering fluid specification used in older Chrysler, Jeep, and Dodge vehicles. If you own a pre-1998 Chrysler, a 1999-2004 Jeep Grand Cherokee WJ, or a 2000 Dodge Dakota, this is the fluid your power steering system was designed for.
MS-5931 is a premium blended hydrocarbon formula, which means it’s petroleum-based rather than ATF-derived. It has a clear to light amber appearance, which immediately distinguishes it from the red color of transmission fluids you might be more familiar with.
While Mopar ATF+4 is the gold standard for newer Chrysler transmissions, it should not be used as a top-up in MS-5931 systems. The formulations are different enough that mixing them risks seal damage and leaks, particularly in the WJ Grand Cherokee. Finding the original Mopar MS-5931 has become difficult since Fiat took over Chrysler. Many suppliers show no stock with no forecasted availability.
Let’s look into MS-5931 equivalents that you can use to top up or replace your power steering fluid.
MS-5931 Equivalent PSFs
Since the original Mopar fluid is increasingly hard to find, using a high-quality MS-5931 power steering fluid equivalent is the best way to maintain your Chrysler, Jeep, or Dodge steering system without risking seal damage.
Valvoline 602241
Valvoline 602241 is a conventional aftermarket power steering fluid that meets Chrysler MS-5931, Ford M2C128-C/D, and GM 9985010 specifications. It’s formulated to prevent leaks, squeals, and wear in older domestic power steering systems.
The fluid appears amber, distinguishing it from red ATF fluids. It’s a conventional hydrocarbon formula with seal conditioners, not synthetic. The pour point of -42°F means it stays fluid in extreme cold, so your pump doesn’t struggle on winter mornings. The flash point of 307.4°F indicates it resists breaking down under high engine bay temperatures.
Viscosity runs between 150-280 SUS at 100°F, which keeps the fluid thick enough to protect the pump while staying thin enough to flow properly. The specific gravity of approximately 0.85-0.90 is typical for petroleum-based power steering fluids.
This is a solid choice when you can’t find the original Mopar MS-5931.
Also compatible with:
- Ford M2C128-C/D
- GM 9985010/1050017
- Subaru, Mercedes-Benz, Mazda, and Volvo (certain applications)
TRIAX POWERFLUID 450 PSF
TRIAX POWERFLUID 450 is a full synthetic ester-blended aftermarket power steering fluid that meets or exceeds multiple OEM specifications, including Chrysler MS-5931; and serves as a direct PSF-3 equivalent for various Hyundai and Kia models.
The pour point of -50°C (-58°F) keeps it flowing in arctic conditions, while the flash point of 160°C (320°F) prevents breakdown under high heat. The viscosity index of 313 is exceptionally high, meaning the fluid maintains consistent thickness whether it’s freezing or scorching outside.
At 40°C, the kinematic viscosity is 19.25 cSt, which provides strong film protection for your pump and rack. At 100°C, it drops to 6.2 cSt, staying thin enough to flow freely without losing its protective qualities. The specific gravity of 0.828 is slightly lower than conventional fluids, typical of synthetic formulations.
Beyond power steering, this fluid works in self-leveling suspensions, hydraulic suspensions, convertible top systems, and traction control hydraulics found in Audi, Mercedes-Benz, BMW, Porsche, and Land Rover.
Also compatible with:
- Pentosin CHF 11S, CHF 202, CHF 7.1
- Mercedes-Benz 236.3, 345.0
- BMW/MINI (multiple part numbers)
- Audi/VW G002000, G002012
- Ford M2C195-A, M2C204-A
- GM 9985010, 12345866
- Chrysler MS-10838, MS-1872, MS-9602 (ATF+4)
- Toyota PSF Type EH
- Nissan PSF-II
- Hyundai/Kia PSF-3, PSF-4
- Subaru K0209A0080
- Volvo 1161529
BlueDevil Power Steering Fluid
BlueDevil Power Steering Fluid is a conventional mineral oil-based aftermarket fluid that meets Chrysler MS-5931, Ford ESW-M2C 128-C/D, and GM 9985010 specifications.
The fluid is formulated to prevent wear and corrosion while reducing squeals and improving steering smoothness. It’s compatible with both mineral oil and synthetic power steering systems, making it suitable for General Motors, Ford, and Chrysler applications where DEXRON-III or similar fluids are recommended.
Unlike BlueDevil’s stop leak variant, this version focuses on maintenance rather than seal repair. It doesn’t contain the aggressive seal conditioners designed to swell hardened seals. Instead, it provides standard protection and lubrication for healthy power steering systems.
Also compatible with:
- Ford ESW-M2C 128-C/D
- GM 9985010
RAVENOL PSF-Y Fluid
RAVENOL PSF-Y Fluid is a fully synthetic aftermarket power steering fluid that meets Chrysler MS-5931, MS-10838, and MS-9933 specifications. It’s formulated with high-quality hydrocrack base oils and specialized additives designed for modern power steering systems in Volkswagen, Mercedes-Benz, and Chrysler vehicles.
The synthetic formulation delivers exceptional cold-weather performance with a pour point of -51°C (-60°F), meaning it flows freely even in extreme arctic conditions. The Brookfield viscosity of 12,800 mPa·s at -40°C confirms this fluid won’t gel or thicken when temperatures drop, protecting your pump during cold starts.
At 40°C, the kinematic viscosity is 34.9 mm²/s (roughly equivalent to 34.9 cSt), dropping to 7.2 mm²/s at 100°C. The viscosity index of 177 is excellent for a power steering fluid, indicating stable thickness across temperature ranges. The flash point of 210°C (410°F) provides strong resistance to thermal breakdown under high engine bay heat.
Also compatible with:
- Chrysler 04883077, 05098158A, MS-10838, MS-9933
- GM 9985010, 1050017, 89020661
- Mercedes-Benz 236.3 (A 000 989 88 03)
- VW G 009 300 A2
- Honda 08206-9002, 08285-P99-01Z-T1
- Mopar 05142893AA
Lubeguard Complete Synthetic Power Steering Fluid
Lubegard Complete is a fully synthetic aftermarket power steering fluid compatible with Chrysler MS-5931, MS-1872, and MS-11655 specifications. It is also compatible with Nissan E-PSF and Nissan PSF-II.
This fluid uses a synthetic base that outperforms conventional formulas in wear protection, temperature stability, and seal longevity.
The kinematic viscosity at 40°C is 26 cSt, which is lower than conventional MS-5931 fluids like Valvoline 602241. This thinner viscosity improves cold-start flow and reduces parasitic drag on the pump. The pour point of -51°C (-60°F) ensures the fluid remains liquid in extreme cold, protecting your pump during winter starts.
Lubegard claims to eliminate whining noises, free sticky pumps, reduce rack stiffness, and inhibit foam and oxidation. It’s formulated to protect seals and hoses, reducing leak risk in aging systems.
Also compatible with:
-
- Chrysler MS-1872, MS-9602 (ATF+4), MS-11655
- Mopar 04883077, 05142893AA, 68088485AA/AB
- GM 9985010, 1050017, 1052884, 89020661, 89021184, 12345866
- Ford M2C195-A, M2C204-A, WSS-M2C204-A2
- Mercedes-Benz 000 989 88 03, 001 989 20 03, 001 989 24 03 10
- Audi/VW G 002 000, G 002 012 (Pentosin CHF 11S), G 004 000 M2, G 055 145 S2
- Pentosin CHF 11S, CHF 202
- Many others
Note: Lubegard offers a separate formula (P/N 24242) specifically for Honda and Acura vehicles.
MS-5931 vs. GM 9985010
MS-5931 is Chrysler’s specification. GM’s equivalent is 9985010, which also appears as GM part number 1050017.
These specifications describe the same type of premium blended hydrocarbon fluid with the same performance characteristics. A quality aftermarket power steering fluid that meets one specification typically meets both.
Valvoline and other major manufacturers formulate their power steering fluids to satisfy both Chrysler MS-5931 and GM 9985010 simultaneously. When you can’t find original Mopar MS-5931 (which is most of the time now), look for a fluid that carries both certifications.
MS-5931 vs. CHF 11S
Several aftermarket manufacturers claim their synthetic fluids work for both MS-5931 and Pentosin CHF 11S specifications, despite fundamental differences between these fluids. They achieve this through advanced synthetic formulations, but the compatibility claims deserve scrutiny.
The core problem is viscosity. CHF 11S runs significantly thinner than MS-5931. Using a thin fluid in an older Saginaw or Chrysler pump designed for thicker MS-5931 can cause groaning, moaning, or whining noises. The pump expects a certain resistance, and when the fluid flows too freely, the hydraulics don’t respond correctly.
Universal synthetic fluids like TRIAX POWERFLUID 450, Lubegard COMPLETE, and similar products bridge this gap through several methods.
They use high-viscosity-index synthetics that maintain stable thickness across extreme temperatures, staying thin enough for arctic CHF 11S applications while thick enough at operating temperature for MS-5931 systems.
They incorporate PAO (polyalphaolefin) and ester base oils that resist shearing under stress. They may also include additive packages with seal conditioners for older systems and friction modifiers for modern electro-hydraulic pumps.
From a business standpoint, these fluids are inventory optimizers. One bottle replaces dozens of OEM-specific products, which benefits retailers and service shops.
However, caution is warranted. If you switch from conventional amber MS-5931 to a thinner universal synthetic and your pump starts groaning, the viscosity likely isn’t right for your specific hardware. Older pumps were designed around specific fluid characteristics, and not all “universal” claims translate to real-world compatibility.
For critical applications in vintage systems, using a fluid explicitly formulated for MS-5931 remains the safest approach.
ATF+4 is NOT an MS-5931 Alternative
Mixing MS-5931 and ATF+4 will damage your power steering system. Chrysler explicitly prohibits using ATF as a top-up or replacement in MS-5931 systems, particularly in pre-1998 Chrysler vehicles and 1999-2004 Jeep Grand Cherokee WJ models.
MS-5931 is formulated with specific seal conditioners that keep O-rings and seals pliable. ATF+4 uses a different additive package that doesn’t provide the same protection. When you introduce ATF into an MS-5931 system, those seals begin to degrade. You’ll start seeing fluid weeping from the rack, pump, or hoses.
MS-5931 is clear to light amber. ATF+4 is red. This visual distinction prevents confusion about what’s actually in your system. If you pop the cap and see pink fluid in a vehicle that calls for MS-5931, someone made a mistake.
Owners who’ve attempted to flush from MS-5931 to ATF+4 report increased pump noise and air entrainment. The fluid aerates, creating bubbles in the reservoir that take multiple steering cycles to work out. The pump whines. The steering feels inconsistent.
Chrysler’s strict power steering fluid requirements stem from component protection. The blended hydrocarbon formula in MS-5931 prevents pump breakdown from wear and oxidation. It resists foaming and maintains viscosity across temperature extremes (pour point of -42°F, flash point of 347°F). The additive package was engineered specifically for the seal materials used in these systems.
Vehicle-specific engineering complicates this further. The 2000 Dakota was factory-filled with MS-5931 even as Chrysler began transitioning newer models to ATF+4. The hardware in that specific build requires the original fluid specification. Using ATF+4 because “it’s newer and better” ignores the fact that the seals weren’t designed for it.
Don’t be surprised if you encounter conflicting information online or even from dealership service advisors. The confusion likely stems from overlapping input from engineers, technical writers, and accountants during Chrysler’s transition period. Some models switched. Others didn’t.
The decision essentially boils down to this: use an aftermarket fluid that explicitly meets MS-5931 specifications, or risk seal failure by substituting ATF+4.
Closing Notes
Using the correct fluid is about maintaining the pliability of rubber components that are now 20 to 30 years old. Those seals don’t care about corporate mergers or what’s easiest to find at the parts store. They only know whether the fluid touching them keeps them soft or causes them to harden and crack.
If you own a pre-1998 Chrysler, a 1999-2004 Jeep Grand Cherokee WJ, or a 2000 Dodge Dakota, don’t settle for ATF+4 just because it’s red and says “Mopar” on the bottle. Find a fluid that explicitly meets MS-5931 specifications, whether that’s Valvoline 602241, Ravenol PSF-Y, Lubegard Complete, or another certified equivalent.
The pump and rack in your vehicle will run quieter and last longer when you give them the hydrocarbon-based fluid they were designed for. Shorter fluid change intervals with the correct specification will always outlast “lifetime fill” with the wrong one.
