Ultraflex Hydraulic Steering System Oil - 1 Litre

The Ultraflex OL150 42398X is a 1-litre low-viscosity ISO VG 15 hydraulic oil for compatible Ultraflex marine hydraulic steering systems. It has a nominal viscosity of 15 cSt at 40°C, a solidification point below -30°C and a published contamination level of NAS 1638 class 8 or cleaner. Ultraflex describes the formulation as resistant to high temperatures and designed to provide wear and corrosion protection. It can also be used in compatible flap systems and other hydraulic mechanisms where OL150 is specified.

Product Identification

• Brand: Ultraflex
• Product range: Hydraulic steering accessories
• Product category: Marine hydraulic steering oil
• Product name: OL150 Hydraulic Oil
• Model: OL150 / OL 150
• Manufacturer part number: 42398X
• Supplier catalogue code: 4-47067
• Store SKU: AF-4-47067
• Pack size: 1 litre
• Approximate volume: 0.26 US gallons
• Viscosity grade: ISO VG 15
• Nominal viscosity at 40°C: 15 cSt
• Solidification point: Below -30°C
• Fluid contamination level: NAS 1638 class 8 or cleaner
• Primary application: Compatible Ultraflex hydraulic steering systems
• Additional applications: Compatible flap systems and hydraulic mechanisms
• Temperature characteristic: Formulated for resistance to high temperatures
• Protection characteristics: Wear and corrosion protection
• Container quantity: One bottle
• Hydraulic components: Not included
• Filling and bleeding equipment: Not included

What Is This Hydraulic Steering Oil Used For?

Ultraflex OL150 is used for filling, topping up, servicing and bleeding compatible marine hydraulic steering systems that specify OL150 or ISO VG 15 steering fluid.

The oil transfers hydraulic pressure between the steering helm and cylinder. When the steering wheel is turned, the helm displaces the fluid through the hydraulic hoses, causing the cylinder to move the outboard engine, sterndrive or rudder linkage.

It is intended for compatible:

• Ultraflex hydraulic steering helm pumps
• Ultraflex hydraulic steering cylinders
• Single-station steering installations
• Multi-station systems where OL150 is specified
• Outboard hydraulic steering systems
• Inboard hydraulic steering systems
• Sterndrive hydraulic steering systems
• Power-assisted hydraulic steering systems where OL150 is specified
• Hydraulic trim-tab or flap mechanisms
• Other hydraulic mechanisms approved for ISO VG 15 OL150 fluid

The fluid does not determine the horsepower, pressure or steering capacity of the system. The helm, cylinder, hoses, fittings and engine or rudder arrangement must remain within their individual manufacturer ratings.

What Is Included?

The Ultraflex OL150 is supplied with:

• One 1-litre bottle of Ultraflex OL150 hydraulic oil
• Sealed container with product identification

Not included:

• Hydraulic steering helm
• Hydraulic steering cylinder
• Hydraulic steering hoses
• Hydraulic fittings
• Steering wheel
• Helm remote-fill adapter
• Oil-bottle filling adapter
• Bleeding hose
• Automatic purging equipment
• Replacement seals
• Additional hydraulic oil

This listing covers one 1-litre bottle only.

Which Hydraulic Steering Systems Are Compatible?

The Ultraflex OL150 is specifically intended for compatible Ultraflex hydraulic steering systems that identify OL150 or ISO VG 15 oil in their installation or maintenance instructions.

Before ordering or adding oil, confirm:

• The system manufacturer specifies Ultraflex OL150 or ISO VG 15 hydraulic steering oil
• The existing helm and cylinder are part of a compatible hydraulic system
• The system does not specify Ultraflex OL460 or another hydraulic fluid
• The existing fluid can be safely mixed with OL150
• The system has not been contaminated with water or another oil
• One litre is sufficient for the system capacity and bleeding procedure
• Any leak or damaged component has been repaired before refilling
• The correct filling and bleeding equipment is available

Do not select hydraulic steering oil solely by boat brand, engine manufacturer or container appearance.

A different fluid may have the same nominal ISO VG grade but use different additives, base-fluid chemistry or seal-compatibility characteristics. Use the oil specified by the steering-system manufacturer.

Which Ultraflex Systems Use OL150?

Ultraflex identifies OL150 as the hydraulic oil used in a range of its packaged steering systems, including compatible GoTech, HyTech, Hyco, Nautech, SilverSteer and MasterDrive configurations.

The exact oil quantity depends on:

• Helm-pump capacity
• Cylinder volume
• Hydraulic-hose length
• Number of steering stations
• Additional autopilot plumbing
• Remote-fill arrangements
• Fluid lost during bleeding

The presence of OL150 in one packaged system does not confirm that every Ultraflex hydraulic product uses the same fluid. Check the manual for the exact helm, cylinder or steering kit.

What Does ISO VG 15 Mean?

ISO VG 15 identifies the oil's nominal viscosity grade.

For OL150, current supplier data gives a nominal kinematic viscosity of:

• 15 cSt at 40°C

A lower-viscosity hydraulic fluid flows more readily through small steering passages and hoses than a heavier hydraulic oil. This helps the helm transfer fluid without creating unnecessary resistance, particularly during lower-temperature operation.

The ISO VG grade does not by itself confirm seal compatibility, additive compatibility, permitted system pressure or compatibility with fluid already in the system.

Always follow the steering-system manufacturer's fluid specification.

Performance Characteristics

• ISO VG 15 viscosity grade
• Nominal viscosity of 15 cSt at 40°C
• Low-viscosity hydraulic formulation
• Designed for resistance to high temperatures
• Wear-protection characteristics
• Corrosion-protection characteristics
• Solidification point below -30°C
• NAS 1638 contamination class 8 or cleaner
• Suitable for compatible marine hydraulic steering systems
• Additional use in compatible flaps and hydraulic mechanisms

The high-temperature statement does not provide a numerical maximum fluid temperature. Follow the operating-temperature limits stated for the complete steering system.

Fluid Properties

• Fluid model: Ultraflex OL150
• Hydraulic-oil grade: ISO VG 15
• Nominal kinematic viscosity at 40°C: 15 cSt
• Solidification point: Below -30°C
• Published contamination level: NAS 1638 ≤8
• Temperature characteristic: High-temperature-resistant formulation
• Protection: Wear and corrosion protection
• Container size: 1 litre
• Manufacturer part number: 42398X

The solidification point is a fluid-property measurement. It must not be treated as the minimum approved operating temperature of the complete steering system.

The current Ultraflex product page does not state a flash point, base-oil chemistry or viscosity index. These values should not be inferred from another brand of hydraulic oil.

What Does NAS 1638 Class 8 or Cleaner Mean?

NAS 1638 is a hydraulic-fluid particle-contamination classification. Ultraflex publishes a contamination level of NAS 1638 ≤8 for OL150.

This identifies the stated cleanliness level of the supplied fluid. Maintaining cleanliness is important because particles entering a hydraulic steering system can affect:

• Helm pump components
• Check valves
• Lock valves
• Cylinder seals
• Hydraulic fittings
• Small fluid passages
• Steering response

Keep the bottle sealed until use and prevent dirt, water, fibres or old contaminated oil from entering the steering system.

How Much Oil Is Required?

This listing supplies one litre of OL150.

The quantity required depends on:

• Helm-pump capacity
• Cylinder volume
• Hydraulic-hose length
• Number of steering stations
• Additional autopilot plumbing
• Remote-fill arrangements
• Fluid lost during bleeding
• Whether the system is being topped up or filled from empty

Some complete Ultraflex steering kits are supplied with two litres of OL150, but this should not be used as a universal quantity for every installation.

Check the installation manual and allow sufficient fluid to complete the full bleeding procedure without allowing the helm reservoir to run dry.

Can OL150 Be Mixed with Existing Hydraulic Fluid?

Do not assume that OL150 can be mixed with an unidentified steering fluid.

Before topping up:

• Identify the oil already present in the system
• Check the steering-system manual
• Confirm that the existing oil is compatible with Ultraflex OL150
• Inspect the fluid for water, dirt, cloudiness or discolouration
• Confirm that a leak is not responsible for the low fluid level

Where the existing fluid cannot be identified, the steering manufacturer may require the system to be drained, flushed and refilled.

Mixing incompatible fluids can affect fluid viscosity, seal compatibility, lubrication, corrosion protection, steering response and system reliability.

Do not add automotive brake fluid, engine oil, gearbox oil or an unapproved automatic-transmission fluid to an Ultraflex steering system.

Can OL150 Be Used for Flaps and Other Hydraulic Mechanisms?

Yes. Ultraflex states that OL150 can also be used for flaps and hydraulic mechanisms.

This does not make OL150 a universal fluid for every trim-tab, flap or hydraulic system. Before use, confirm that the equipment manufacturer specifies:

• Ultraflex OL150
• ISO VG 15 hydraulic oil
• A fluid with compatible material and seal requirements
• A fluid suitable for the mechanism's pressure and temperature range

Do not substitute OL150 where a different hydraulic-oil grade or proprietary fluid is specified.

Filling and Bleeding the Steering System

Marine hydraulic steering is safety-critical. Follow the installation and bleeding instructions for the exact Ultraflex helm and cylinder.

Before filling:

• Repair all known leaks
• Inspect the helm, cylinder, hoses and fittings
• Clean the area around the helm filler
• Keep the bottle sealed until required
• Use clean filling and bleeding equipment
• Confirm the specified fluid type
• Confirm the correct helm-filler orientation
• Prevent dirt or water from entering the system

During filling and bleeding:

• Follow the manufacturer's stated bleeding sequence
• Keep the helm reservoir or oil bottle sufficiently full
• Do not allow the helm to draw in air
• Bleed both cylinder sides where required
• Turn the wheel in the specified direction
• Continue until the discharged fluid contains no visible air bubbles
• Do not return discharged or contaminated oil to the new bottle
• Tighten bleed fittings according to the system instructions

After bleeding:

• Turn the wheel through the complete steering range
• Confirm consistent movement in both directions
• Check that the cylinder reaches its permitted travel
• Inspect all hose and fitting connections for leaks
• Check the helm-fluid level
• Refit the filler plug securely
• Check for excessive wheel movement or delayed cylinder response
• Recheck the fluid level after initial operation

Do not operate the boat if the steering feels spongy, has excessive free movement, leaks oil or does not reach its full travel.

Storage and Handling

• Keep the bottle in its original labelled container
• Store the container upright
• Keep the cap securely closed
• Protect the fluid from water, dirt and other contamination
• Store away from excessive heat and ignition sources
• Do not transfer the oil into an unlabelled container
• Do not return used fluid to the original bottle
• Clean spills with an appropriate absorbent material
• Dispose of used hydraulic oil through an authorised waste-oil facility
• Follow the current safety data sheet and local handling requirements

Hydraulic oil must not be discharged into bilges, drains, soil or waterways.

Frequently Asked Questions

What is Ultraflex OL150 used for?

It is an ISO VG 15 hydraulic oil for compatible Ultraflex marine hydraulic steering systems. Ultraflex also lists compatible flaps and hydraulic mechanisms as additional applications.

What is the manufacturer part number?

The Ultraflex part number is 42398X.

What is the supplier catalogue code?

The UK supplier code is 4-47067.

How much oil is supplied?

The container holds one litre, approximately 0.26 US gallons.

What is the oil viscosity?

The grade is ISO VG 15, with a supplier-published nominal viscosity of 15 cSt at 40°C.

What is the solidification point?

Ultraflex states a solidification point below -30°C. This is not the same as the approved minimum operating temperature of the complete steering system.

Can it be used in every hydraulic steering system?

No. Use OL150 only where the steering-system manufacturer specifies OL150, ISO VG 15 or confirms compatibility.

Can it be used with Ultraflex GoTech steering?

OL150 is included in Ultraflex GoTech packaged steering systems. Check the exact kit or component manual for the quantity required.

Can it be used for hydraulic trim tabs or flaps?

Yes, where the flap or hydraulic-mechanism manufacturer specifies a compatible ISO VG 15 fluid. Ultraflex lists flaps and hydraulic mechanisms as additional OL150 applications.

Can OL150 be mixed with another steering oil?

Do not assume compatibility. Identify the existing fluid and check the steering-system manual before mixing or topping up.

Is a filling or bleeding kit included?

No. This listing covers one bottle of hydraulic oil only.

Does one litre fill a complete steering system?

It depends on the helm, cylinder, hose length and bleeding losses. Some systems require more than one bottle.

Is this engine oil or gearbox oil?

No. OL150 is hydraulic oil for compatible steering and hydraulic mechanisms.

Is a viscosity index published?

The current Ultraflex product page does not state one. Conflicting third-party values have therefore not been used.

Key Features

• Ultraflex OL150 hydraulic steering oil
• Model OL150 / OL 150
• Manufacturer part number 42398X
• Supplier catalogue code 4-47067
• Store SKU AF-4-47067
• One-litre bottle
• Approximately 0.26 US gallons
• ISO VG 15 hydraulic-oil grade
• Nominal viscosity of 15 cSt at 40°C
• Low-viscosity formulation
• Specifically intended for compatible Ultraflex hydraulic steering systems
• Suitable for filling, topping up, servicing and bleeding
• Solidification point below -30°C
• NAS 1638 contamination class 8 or cleaner
• Formulated for resistance to high temperatures
• Provides wear protection
• Provides corrosion protection
• Can also be used in compatible flap systems
• Can also be used in approved hydraulic mechanisms
• Hydraulic steering components supplied separately
• Filling and bleeding equipment supplied separately
• Existing-fluid compatibility must be confirmed before mixing
• Required oil quantity depends on the complete steering system