Aviation Oils, Greases & Aircraft Lubricants

Aircraft engines, airframes, bearings, and hydraulic systems have specialized lubrication requirements that differ from automotive and general industrial equipment.

Keller Heartt carries aviation oils, greases, and specialty fluids for aircraft maintenance applications, including products from AeroShell with additional aviation lubricant options continuing to be added.

Always select an aviation lubricant according to the specifications and approvals required by the aircraft, engine, or individual component manufacturer.

How Do I Choose the Right Aviation Lubricant?

Start with the component being lubricated and the specification required for that equipment.

The product name or viscosity alone should not determine which aviation lubricant is used.

Aviation Piston Engine Oils

Aircraft piston engines require oils specifically formulated and approved for aviation service.

Aviation piston engine oils may be available as:

• Straight mineral oils

• Ashless dispersant oils

• Single-grade oils

• Multigrade oils

• Specialty formulations with additional anti-wear or corrosion protection

The correct oil depends on the engine manufacturer's requirements, ambient temperature, engine condition, and operating environment.

Single-Grade vs. Multigrade Aviation Oil

One of the most common aviation oil decisions is whether to use a single-grade or multigrade oil.

Single-grade aviation oil

Single-grade oils are formulated around one primary viscosity range and may be selected based on operating temperature and engine recommendations.

They are commonly used in aircraft operating within relatively predictable temperature conditions.

Multigrade aviation oil

Multigrade oils are designed to flow more readily during colder starts while maintaining the required viscosity as operating temperature increases.

This can make multigrade products useful for aircraft operating across wider seasonal temperature ranges.

Neither type is automatically better. The correct choice depends on the engine manufacturer's approved lubricant recommendations and operating conditions.

What Is Ashless Dispersant Aviation Oil?

Ashless dispersant oils contain additive chemistry designed to keep combustion byproducts and contaminants suspended in the oil rather than allowing them to form deposits inside the engine.

The term ashless refers to an additive system formulated to avoid metallic ash deposits.

Many commonly used aviation piston engine oils are ashless dispersant products, including several of the AeroShell oils currently carried by Keller Heartt.

Understanding Aviation Oil Viscosity

Aviation oils are available in different viscosity grades because operating temperature affects how easily oil flows and how effectively it maintains a lubricating film.

In general:

• Lower-viscosity aviation oils flow more readily at lower temperatures.

• Higher-viscosity oils maintain a thicker film as temperatures rise.

• Multigrade oils are designed to provide a broader operating-temperature range.

The aircraft or engine manufacturer's documentation should determine the appropriate viscosity rather than choosing a grade based only on climate.

AeroShell Aviation Oils

AeroShell is one of the aviation lubricant brands currently available from Keller Heartt.

The assortment includes several piston engine oils designed for different viscosity and operating requirements.

AeroShell W80

AeroShell W80 is a single-grade ashless dispersant piston engine oil generally associated with cooler operating conditions when approved by the engine manufacturer.

AeroShell W100

AeroShell W100 is a higher-viscosity single-grade ashless dispersant aviation oil commonly used where an SAE 50 aviation oil is specified.

AeroShell W100 Plus

AeroShell W100 Plus builds on the W100 formulation with additional anti-wear and corrosion-protection additives.

AeroShell W 15W-50

AeroShell W 15W-50 is a multigrade piston engine oil designed to provide broader temperature performance than a traditional single-grade oil.

Aviation Greases

Aircraft use grease in components where a fluid oil would not remain in place effectively.

Depending on the aircraft and component, aviation grease may be used for:

• Wheel bearings

• Landing gear

• Hinges

• Actuators

• Airframe lubrication points

• Electric motors

• Control mechanisms

• Other high-load or temperature-sensitive components

The correct grease should be chosen based on the required specification, operating temperature, component type, load, and material compatibility.

AeroShell Grease 22 vs. Grease 33

Two AeroShell greases currently represented in Keller Heartt's assortment serve different aviation applications.

AeroShell Grease 22

AeroShell Grease 22 is intended for demanding applications involving higher loads, broad temperature ranges, and components such as wheel bearings and other approved aircraft lubrication points.

AeroShell Grease 33

AeroShell Grease 33 is a multipurpose airframe grease used across a range of approved aircraft lubrication applications.

Aviation Hydraulic Fluids

Aircraft hydraulic systems require fluids formulated for aviation service rather than standard industrial hydraulic oil.

Aviation hydraulic fluid may be used in systems such as:

• Landing gear

• Braking systems

• Flight-control systems

• Actuation equipment

• Other aircraft hydraulic components

The correct hydraulic fluid must match the specification required by the aircraft or component manufacturer.

AeroShell Fluid 41 is one aviation hydraulic fluid currently available from Keller Heartt.

Why Aviation Lubricant Specifications Matter

Aviation lubricant selection should be based on approved specifications, not simply on viscosity or brand.

Depending on the application, requirements may come from:

• Aircraft manufacturers

• Engine manufacturers

• Component manufacturers

• SAE standards

• Military specifications

• Other aviation-industry standards

Before changing brands or lubricant types, confirm that the new product meets the specifications required for the aircraft and application.

This is especially important when comparing products from different aviation lubricant manufacturers.

Can Aviation Lubricants From Different Brands Be Cross-Referenced?

Potentially, but a cross-reference should be treated as a starting point rather than proof that two products are interchangeable.

Before replacing one aviation lubricant with another, compare:

• Required specification

• Viscosity

• Lubricant type

• Base oil

• Additive chemistry

• Component compatibility

• OEM approvals

The aircraft or equipment manufacturer's requirements should determine whether the substitute is acceptable.