Oils and Lubricants for Off Highway Equipment

Off-highway equipment is subject to not only the worst of the weather but also high workloads and punishing schedules whether in quarries, road making or site work.

Off highway and construction equipment utilises many lubricants from engine oils, hydraulics, gear oils, track drives, wet braking systems, greases, and coolants. In this brief overview we will concentrate on the following areas:

  • Engine oils
  • Hydraulics
  • Wet braking systems


Engine Oils

Off highway equipment utilises engines for many purposes. Motive power directly coupled through conventional drives, hydrostatic drives, PTO’s (Power Take Off), electrical power supply amongst others. The stresses of simple motive power do not apply and therefore the assumption that normal engine oils are sufficient is incorrect. One example of this is an excavator. Motive power is supplied through hydraulics to each track allowing the vehicle to get to where its needed. As control is direct to each track, precise locating is possible without large turning circles. Once in position engine power is directed towards the hydraulic arms and slew gears. This arrangement allows 360° movement of the bucket or other implement attached for loading, excavating or any of the plethora of work possible.

Loadings on engine oils in off highway applications is completely different to that of typical cars, vans, trucks etc. The working environment can be varied from cold days and nights on exposed moors to mid-Summer heat within moderate climates to the extremes of desert heat in global applications.

When choosing engine oils for your off-way equipment ensure the proposed lubricant has been optimised for the application. Heavy duty engine oils are required with high levels of detergency and dispersancy to ensure engines run clean and reduce wear. Lesser engine oils may seem a reduction in operating costs but will eventually lead to increased maintenance costs due to increased wear, piston deposits both within the combustion chamber and the ring pack, sludging and loss of performance at the extremes of usage.


If we take the example of an excavator, hydraulics is a fundamental part of the equipment. A simple ISO VG 46 HLP hydraulic may well work in the equipment but its limitations will soon be realised. As the working day progresses the temperature of hydraulic oils increases until a threshold moment is obtained. Once the viscosity of a fluid reduces to this critical point the amount of work reduces as equipment becomes slower. Whilst you can increase the viscosity to partially offset this effect, lower temperature will be affected with higher viscosities, straining on pumps and drives.

To optimise work rates and longevity OEM recommended specifications should be used. In excavators’ typical recommendations would be HVLP or HVLP-D allowing operation across a varied temperature range.

Wet Braking Systems

Oil immersed brakes are common in off-highway equipment for many reasons. Special oils should only be used to ensure not only the elimination of noise and judder but also the life of frictional materials. Commonly known as UTTO or in some cases Universal oils; however, with engine requirements the days of a single engine, hydraulic and braking oil are limited.

Wet braked have discs submerged in oil to give cooling. Overheating brakes can cause braking fade which extends braking distance. Immersed brakes are also protected from the working environment i.e. dust, water which are commonplace on construction sites and quarries. Whilst out board brakes are cheaper to maintain, oil immersed brakes last longer and given the working environment will deliver what is a vital requirement.

Whatever the application, optimised performance can only be achieved by using the correct oils from a reputable supplier. Lubricants are an essential part of any equipment and the correct lubricants will not only prolong the life of equipment but in the long term reduce operating costs and increase productivity.

Exol Lubricants oil finder is an excellent tool for selecting the right oil for your off highway equipment with information on capacities to further assist: https://www.exol-lubricants.com/oil-check/