Choosing the Right Lubricants & Lubricant Supplier for your Fleet

Whether a fleet has 6 or 60 vehicles, choosing the right motor oils and lubricants is vital to reduce breakdowns, downtimes, maintenance costs and to increase the life of your engine and drive train. There are many factors to consider when purchasing lubricants and to merely focus on price per litre can increase over all costs in the long term.

Approved products supplied into the marketplace are not only the result of many years of development and engine trials, they carry manufacturer approval, maintaining warranties in the after sales market giving piece of mind in the event of component failures.

Over the course of this article we will look at the various aspects of lubricant design and support offered by reputable lubricant suppliers to help you make informed choices when purchasing motor oils for your fleet.

European Emission Standards

Concerns around global warming and atmospheric pollution are not new and have been around for many years. As part of a program to reduce pollutants the EU created standards to help make trucks and buses run cleaner with a rolling program started nearly 30 years ago.

 Euro Standard

 Introduction Date

 Euro 1

  31st December 1992

 Euro 2

  1st January 1997

 Euro 3

  1st January 2001

 Euro 4

  1st January 2006

 Euro 5

  1st January 2011

 Euro 6

  1st September 2015

Understanding Oil specifications

These can be a confusing mix of numbers and letters which are often confused with exhaust emissions. The European Automobile Manufacturers’ Association or ACEA has defined oil specifications known as ACEA Oil Sequences. For heavy duty applications we need to consider “E” class a numbers.


This class of oils has high levels of detergency to keep engines clean and free from deposits both within the engine and the combustion chamber, especially on pistons, the ring pack, and valves. E4 was the first of the “long drain” oils and was adopted by many OEM’s for this purpose. E4 oils are not classed as low SAPs (Sulphated Ash Phosphorus and Sulphur) and are not recommended for vehicles with DPF, particle traps or any exhaust after treatment sensitive to ash levels.


E6 lubricants are the natural progression from E4 bringing both long drain and low SAPs allowing their use in vehicles fitted with both DPF and catalyst exhaust aftertreatment devices.


This category was the progression from E3, E5 to E7 today. Typically, mineral oil based this grade suits most engines without exhaust after treatment devices. Still a very popular grade of lubricant as it also commands a lower price than other E9 Sequences.


E9 oils are very similar to E7; however, they have been formulated with strict SAPs limits. They are low-SAPS oils and designed for trucks having exhaust aftertreatment devices such as DPF. Although still mineral-based, E9 oils use Group II base oils which generally makes E9 more expensive than E7.

Manufacturer Specifications

To complicate matters, OEM’s have their own oil specifications. In most cases these are based upon ACEA sequences with additional requirements and field testing beyond the standard ACEA requirements. E.g. many E7 oils have Renault RLD-2, Volvo VDS-3 and MAN M 3275 or E6 having MB 228.51, MAN 3477. The table below shows that fleets of varying manufacturers can be covered by a reduced oil inventory; however, the one size fits all days are long gone.



Guide ACEA Oil Sequence










 Mercedes Benz

MB 228.3

MB 228.31

MB 228.5

MB 228.51















This table is provided for informative purposes only and should not be used to interpret individual specifications given by an OEM.























Condition Monitoring – Preventative maintenance

Lubricant oil monitoring is an essential part of any operators’ fleet. Early indications of coolant leaks, fuel dilution, wear can prevent not only breakdowns, but very expensive engine or gearbox replacements can be avoided with early diagnosis. Exol Lubricants runs a program called Fluid Check which is aimed at providing:

  • Optimised lubricant oil changes
  • Reduced operating costs
  • Anticipate and plan maintenance
  • Increase equipment life
  • Improve reliability and performance

For further information please refer to our website:

Fuel Efficient Oils and Fuel Economy (FE)

Engines spend a large proportion of time operating at hotter temperatures, hence the viscosity at higher temperatures is more likely to affect fuel economy. The limiting factor is the oil film and strength afforded by the lubricant in question. Whilst synthetics have a thinner oil film and high strength, the HTHS (High Temperature High Shear) value must be maintained. For E4 to E9 this would be > 3.5 mPa┬Às @150°C which can be achieved by an 5W-30 or 10W-30 engine oil providing the oil can be proven to stay in grade (ASTM D7109) without evaporative loses exceeding 13% (Noack CEC L-040-93).

Engine wear protection limits oil viscosity to an SAE XW-30, limiting the fuel economy potential. Lower temperature requirements help with fuel efficiency as the overall viscous drag is reduced; however, this is not as great a contribution.

Fuel economy gains of 2.0 to 4.0% are possible; however, this would depend on the baseline used for comparison. If a trial has been done replacing an SAE 15W-40 with an SAE 5W-30 then the saving would be heavily exaggerated compared with a similar 10W-40.

If fuel efficient lubricant oils are to be used, this should be done in conjunction with your lubricant supplier and OEM recommendations. Any savings gained on fuel could easily be wiped out by losses due to wear.

Fuel economy obtained from lubricants can only be realised if the vehicle is been driven economically. Harsh braking, accelerating, poor gear changes, terrain, urban traffic all contribute and should be taken into consideration before making lubricant choices. Driver trainer alone can return excellent benefits without changing lubricants to FE grades which normally command a higher price.

Fleet Oils – Single and Multi-OEM

The biggest bone of contention with any lubricant supply is rationalisation of lubricants. If the customer has a single OEM – very rare – then this can be done with relative ease; however, most will operate various manufacturers for a multitude of reasons.

It is possible to run a mixed fleet such as:
DAF, Volvo, MAN, Mercedes Benz, IVECO, Scania, Renault

Using a single oil providing they are all within the same age range and Euro status. Complications arise when you have mixed ages and Euro status where the use of a synthetic 5W-30 in a 10-year-old truck may not be the best approach.

The best way to optimise lubricant use and efficiency is to work with your lubricant supplier. Exol Lubricants offers a cradle to grave approach with guidance on purchases, condition monitoring in use, advice on oil drain intervals and the responsible way to dispose of your used lubricants and motor oils.