Mobil DTE 25 Ultra Hydraulic Oil
ISO VG 46 Antiwear Hydraulic Oil for High-Pressure Industrial Systems
Mobil DTE 25 Ultra is a high-performance ISO VG 46 antiwear hydraulic oil designed for demanding industrial hydraulic systems using high-pressure, high-output pumps and precision hydraulic components.
Part of the Mobil DTE 20 Ultra Series, it provides wear protection, strong oxidation and thermal stability, deposit control, corrosion protection and controlled water separation. Its keep-clean performance is especially useful in modern hydraulic systems with close-clearance servo and proportional valves where sludge or deposits can interfere with reliable operation.
Mobil DTE 25 Ultra is the ISO VG 46 grade in the series and is the current high-performance replacement for legacy Mobil DTE 25 in compatible applications.
Key Benefits
- ISO VG 46 hydraulic oil
- High-performance antiwear formulation
- Designed for high-pressure hydraulic systems
- Suitable for high-output hydraulic pumps
- Helps protect pumps, gears, bearings and valves
- Strong deposit and sludge control
- Keep-clean performance for tight-tolerance components
- Excellent oxidation and thermal stability
- Controlled demulsibility for water separation
- Enhanced corrosion protection
- Strong foam control
- Suitable where limited water contamination may occur
- Designed for systems requiring high load-carrying capability
- Up to 2X longer oil drain intervals versus qualifying competitive hydraulic oils in Mobil testing
- Arburg Hydraulic Fluid approved
- Bosch Rexroth Fluid Rating List 90245 approved
- Denison HF-0, HF-1 and HF-2 approved
- Eaton E-FDGN-TB002-E approved
- Husky approved
- Recommended for applications requiring Fives Cincinnati P-70
- Meets current DIN 51524-2 and ISO 11158 L-HM requirements
ISO VG 46 Hydraulic Oil
Mobil DTE 25 Ultra is classified as ISO VG 46.
Typical viscosity properties are:
- Kinematic viscosity at 40°C: 46.2 mm²/s
- Kinematic viscosity at 100°C: 7.1 mm²/s
- Viscosity Index: 110
ISO VG 46 should only be used where the equipment manufacturer specifies or permits that viscosity grade.
Antiwear Protection for Hydraulic Pumps
Hydraulic pumps operate under high loads, tight clearances and repeated pressure cycles.
Mobil DTE 25 Ultra is formulated to provide antiwear protection in hydraulic systems using components such as:
- Vane pumps
- Piston pumps
- Gear pumps
- Bearings
- Hydraulic gears
- Servo valves
- Proportional valves
Its current approval list includes Bosch Rexroth Fluid Rating List 90245, Denison HF-0/HF-1/HF-2 and Eaton E-FDGN-TB002-E.
Keep-Clean Performance
Modern hydraulic systems can be sensitive to sludge, varnish and oxidation deposits.
This is particularly important in systems containing:
- Close-clearance servo valves
- Proportional valves
- Precision controls
- CNC equipment
- Automated production machinery
Mobil DTE 25 Ultra is formulated with keep-clean performance to help reduce system deposits and sludge.
Extended Hydraulic Oil Life
Mobil reports that DTE 20 Ultra Series oils have demonstrated up to 2 times longer oil drain intervals compared with similar competitive hydraulic oils under its specified comparison conditions.
The comparison is against qualifying hydraulic oils with approximately 100 viscosity index, zinc-based antiwear chemistry and at least ISO 11158 L-HM and/or DIN 51524-2 HLP performance.
Actual hydraulic oil life depends on:
- Operating temperature
- Contamination
- Water ingress
- Filtration
- System design
- Reservoir size
- Duty cycle
- OEM recommendations
Oil analysis should be used when extending drain intervals beyond established equipment maintenance schedules.
Oxidation and Thermal Stability
High hydraulic-system temperatures can accelerate lubricant oxidation.
Oil oxidation can contribute to:
- Varnish
- Sludge
- Oil thickening
- Filter restriction
- Valve deposits
Mobil DTE 25 Ultra is formulated for strong oxidation and thermal stability to help control deposits and maintain lubricant performance under demanding service conditions.
Water Separation and Demulsibility
Water can enter industrial hydraulic systems through condensation, washdown, leaking seals or environmental exposure.
Mobil DTE 25 Ultra provides controlled demulsibility to help separate water from the hydraulic fluid so that it can be removed from the system.
The current technical data lists 20 minutes to 3 mL emulsion at 54°C under ASTM D1401.
Mobil also identifies the DTE 20 Ultra Series for systems where small amounts of water are unavoidable. Significant or recurring water contamination should still be investigated and corrected.
Corrosion Protection
Typical current test results include:
- ASTM D665 Procedure B Rust Test: Pass
- ASTM D130 Copper Strip Corrosion: 1A
These standardized test results characterize the oil's corrosion-protection performance in compatible hydraulic systems.
Systems Containing Gears and Bearings
Mobil specifically includes hydraulic systems containing gears and bearings among DTE 20 Ultra applications.
Mobil DTE 25 Ultra has a typical FZG Scuffing Fail Load Stage of 11.
Mobil DTE 25 Ultra remains a hydraulic oil and should not be substituted for a dedicated industrial gear oil where gear oil is specified.
CNC and Precision Hydraulic Systems
Mobil specifically recommends the DTE 20 Ultra Series for hydraulic systems where deposit buildup can interfere with reliable operation.
Potential applications include:
- CNC machine tools
- Injection molding equipment
- Hydraulic presses
- Automated manufacturing equipment
- Hydraulic power units
- Precision machining equipment
- Systems using servo valves
- Systems using proportional valves
Injection Molding Equipment
Mobil DTE 25 Ultra carries Arburg Hydraulic Fluid and Husky approvals.
These approvals are particularly relevant to compatible injection molding and plastics-processing equipment. Verify the individual machine manufacturer's fluid requirement before use.
Foam Control
Typical ASTM D892 foam tendency/stability results are:
- Sequence I: 10/0 mL
- Sequence II: 10/0 mL
- Sequence III: 10/0 mL
Foam control helps support consistent hydraulic response and reduce problems associated with entrained air.
Is Mobil DTE 25 Ultra Zinc-Free?
No. Mobil DTE 20 Ultra products contain zinc-based antiwear chemistry.
This distinction is important for equipment or applications that specifically require a zinc-free hydraulic oil.
Mobil DTE 25 Ultra vs. Mobil DTE 25
Mobil DTE 25 Ultra is the newer high-performance ISO VG 46 product in the Mobil DTE 20 Ultra Series.
Mobil has identified the older Mobil DTE 20 Series for retirement and states that corresponding DTE 20 Ultra grades can replace the legacy products in compatible applications.
Mobil DTE 25 Ultra is the current ISO VG 46 replacement for Mobil DTE 25.
Mobil also states that DTE 20 Ultra products are compatible with their corresponding legacy DTE 20 Series fluids. For best performance when converting products, draining the previous fluid before filling with DTE 25 Ultra is preferred.
Current Approvals
- Arburg Hydraulic Fluid
- Bosch Rexroth Fluid Rating List 90245
- Denison HF-0
- Denison HF-1
- Denison HF-2
- Eaton E-FDGN-TB002-E
- HOCNF Norway-NEMS, Black
- Husky
Recommended for Applications Requiring
Meets or Exceeds
- ASTM D6158 Class HMHP
- China GB 11118.1-2011 L-HM General
- China GB 11118.1-2011 L-HM High Pressure
- DIN 51524-2:2017-06
- ISO L-HM, ISO 11158:2023
- JCMAS HK VG46
Typical Technical Properties
| Property |
Typical Value |
| ISO Viscosity Grade |
46 |
| Density at 15.6°C |
0.8667 kg/L |
| Kinematic Viscosity at 40°C |
46.2 mm²/s |
| Kinematic Viscosity at 100°C |
7.1 mm²/s |
| Viscosity Index |
110 |
| Pour Point |
-33°C |
| Flash Point, COC |
238°C |
| FZG Scuffing Fail Load Stage |
11 |
| Copper Strip Corrosion |
1A |
| Rust Characteristics, Procedure B |
Pass |
| Emulsion, Time to 3 mL at 54°C |
20 min |
| Total Acid Number |
0.7 mg KOH/g |
| Foam Sequences I / II / III |
10/0 mL each |
Typical properties represent normal production values and should not be treated as guaranteed batch specifications.
Frequently Asked Questions
What is Mobil DTE 25 Ultra?
Mobil DTE 25 Ultra is a high-performance ISO VG 46 antiwear hydraulic oil designed for demanding industrial hydraulic systems.
What viscosity is Mobil DTE 25 Ultra?
Mobil DTE 25 Ultra is ISO VG 46. Its typical kinematic viscosity is 46.2 mm²/s at 40°C and 7.1 mm²/s at 100°C.
Is Mobil DTE 25 Ultra the replacement for Mobil DTE 25?
Yes. Mobil identifies the DTE 20 Ultra Series as the replacement for corresponding legacy Mobil DTE 20 Series products. Mobil DTE 25 Ultra is the ISO VG 46 replacement for Mobil DTE 25.
Can Mobil DTE 25 Ultra be mixed with Mobil DTE 25?
Mobil states that DTE 20 Ultra products are compatible with the corresponding legacy DTE 20 Series oils. For best performance, draining the previous oil before converting is preferred.
Is Mobil DTE 25 Ultra zinc-free?
No. Mobil DTE 20 Ultra products contain zinc-based antiwear chemistry.
Is Mobil DTE 25 Ultra an antiwear hydraulic oil?
Yes. Antiwear protection is one of its primary functions.
Is Mobil DTE 25 Ultra suitable for high-pressure hydraulic systems?
Yes. It is specifically designed for hydraulic systems using high-pressure, high-output pumps.
Can Mobil DTE 25 Ultra be used in CNC machines?
Yes. Mobil specifically identifies numerically controlled machine tools and hydraulic systems with close-clearance servo valves among DTE 20 Ultra applications.
Can Mobil DTE 25 Ultra be used in injection molding machines?
Yes, in compatible equipment. Mobil DTE 25 Ultra carries Arburg Hydraulic Fluid and Husky approvals.
Is Mobil DTE 25 Ultra approved by Bosch Rexroth?
Yes. Mobil currently lists Bosch Rexroth Fluid Rating List 90245 among the product's approvals.
Does Mobil DTE 25 Ultra have Denison approval?
Yes. Mobil lists Denison HF-0, HF-1 and HF-2 approvals.
Is Mobil DTE 25 Ultra approved by Eaton?
Yes. Eaton E-FDGN-TB002-E is listed as an approval.
Is Mobil DTE 25 Ultra approved by Husky?
Yes. Husky is listed among the current approvals for DTE 25 Ultra.
Does Mobil DTE 25 Ultra meet Cincinnati P-70?
Mobil recommends DTE 25 Ultra for applications requiring Fives Cincinnati P-70.
Does Mobil DTE 25 Ultra meet DIN 51524-2?
Yes. Current Mobil information lists DIN 51524-2:2017-06 among the requirements met or exceeded.
Does Mobil DTE 25 Ultra meet ISO 11158?
Yes. Current Mobil information lists ISO L-HM under ISO 11158:2023.
What does ISO VG 46 mean?
ISO VG 46 is an industrial lubricant viscosity classification. Oils in this grade have a nominal kinematic viscosity of approximately 46 mm²/s at 40°C.
What is the viscosity index of Mobil DTE 25 Ultra?
The typical viscosity index is 110.
What is the pour point of Mobil DTE 25 Ultra?
The typical pour point is -33°C.
What is the flash point of Mobil DTE 25 Ultra?
The typical Cleveland Open Cup flash point is 238°C.
Does Mobil DTE 25 Ultra separate from water?
Yes. It has controlled demulsibility designed to help water separate from the hydraulic oil so it can be removed from the system.
Can Mobil DTE 25 Ultra be used where some water contamination occurs?
Mobil identifies the DTE 20 Ultra Series for hydraulic systems where small amounts of water may be unavoidable. Significant water contamination should still be corrected.
Does Mobil DTE 25 Ultra help control sludge and deposits?
Yes. Keep-clean performance and deposit control are major features of the DTE 20 Ultra formulation.
Can Mobil DTE 25 Ultra provide longer oil life?
Mobil reports up to 2X longer oil drain intervals compared with qualifying competitive hydraulic oils under specified comparison conditions. Actual service life depends on equipment condition, temperature, contamination, filtration and maintenance practices.
Can Mobil DTE 25 Ultra be used in hydraulic systems containing gears and bearings?
Yes. Mobil specifically includes systems containing gears and bearings among DTE 20 Ultra applications.
Is Mobil DTE 25 Ultra a gear oil?
No. It is an ISO VG 46 antiwear hydraulic oil. Its suitability for hydraulic systems containing gears does not make it a substitute for dedicated industrial gear oil where gear oil is specified.
How often should Mobil DTE 25 Ultra be changed?
Follow the equipment manufacturer's maintenance recommendations and use oil analysis when considering extended drain intervals. Mobil's up-to-2X result is comparative product performance rather than a universal drain schedule.
