Our Frequently Asked Questions (FAQ) page will answer the most frequently asked questions about lubricants.
Which are the functions of a lubricants?
A lubricant may have several functions. The main ones are:
How is a lubricant made?
- Keep surfaces separate under all loads, temperatures and speeds, thus minimising friction and wear
- Act as a cooling fluid removing the heat produced by friction or from external sources
- Remain adequately stable in order to guarantee constant behaviour over the forecasted useful life
- Protect surfaces from the attack of aggressive products formed during operation
- Show cleaning capability and dirt holding capacity in order to remove residue and debris that may form during operation.
The formulation of a lubricant is made up of base oils and additives that combine to determine behaviour when in use, both in terms of performance and in terms of duration.
The final quality of lubricating oil usually depends on the quality of the base oils used, which are generally distinguished as either:
Which are the main properties of a lubricant?
- mineral oils: obtained from the distilling process in the refining of crude oil
- synthetic oils: which are derived from particular physical/chemical laboratory treatments
The main properties of lubricants, which are usually indicated in the technical characteristics of the product, are:
Which are the benefits of synthetic base oils lubricants?
Viscosity describes the flow behaviour of a fluid. The viscosity of lubricating oils diminishes as temperature rises and consequently is measured at a given temperature (e.g. 40°C).
- Viscosity index
The viscosity index is a characteristic used to indicate variations in the viscosity of lubricating oils with changes in temperature. The higher the level of the viscosity index, the lower the variation in viscosity at temperature changes.
- Pour point
The pour point refers to the minimum temperature at which a lubricant continues to flow. Below the pour point, the oil tends to thicken and to cease to flow freely.
- Flash point
The flash point is the minimum temperature at which an oil-vapour-air-mixture becomes inflammable.
How to choose the right engine oil?
- Lower level of volatility to a comparable level of viscosity (which leads to lower consumption during use)
- Higher viscosity index (a wider temperature gap)
- Greater chemical stability at high temperatures (longer useful life)
In order to choose the best motor oil the manufacturer's recommendations should always be followed. To identify the most appropriate lubricant it is therefore necessary to:
Is this the right Eni engine oil for the car in the workshop?
- Consult the section in the vehicle's maintenance guide concerning lubrication
- Identify the manufacturer's suggested viscosity level (e.g. 5W-30, 15W-40, etc)
- Identify the performance specifications required by the manufacturer (e.g. ACEA A3/B4, VW 505.00, etc)
- Choose among the Eni product range the lubricant that can guarantee the viscosity and the strict specifications of constructors.
The right engine oil to be used is given by the proper combination of viscosity and specification profile required by the OEM. While there are various engine oils in the market the first step for the user is quite simple, follow the prescription of the car’s manual. As an alternative consult the Eni Lube Finder by using your vehicle registration plate or by searching for your vehicle. The Eni Lube Finder will recommend the engine oil to be used. In case of doubt you can always contact our Eni technical support or our local distributors.
Can engine oil with the latest specifications be used in vehicles for which an older specification was prescribed?
There is not a general rule. While this is true for example for the API categories which are backward compatible, this is not true for the ACEA categories, for example the C5 category of ACEA is not backward compatible with the other C categories.
For the OEM specification the same principle is valid, there is not a general rule, one needs to know the single specification and follow the indication of the OEM. The best advice we can give is to follow the user’s manual or ask Eni personnel for technical support.
What are the ACEA oil Sequences?
ACEA is the European Automobile Manufacturers' Association and the organization that represents the 15 most important European motor vehicle manufacturers. Among the activities of ACEA there is the definition of the engine oil specifications, so called ACEA Oil Sequences. The sequences, which are updated every few years in order to keep in consideration the latest engine technology development, set the standard for the engine oil. The ACEA oil sequences provide 3 different engine oil categories identified by a letter, each category has different classes, identified by a number, each class meets the requirement of a specific engine.
The different ACEA categories are:
A/B: gasoline and diesel engine oils, suitable for passenger cars without exhaust treatment device.
·A5/B5 offer higher fuel economy due to the lower level of HTHS and need to be used only in the engine which are designed for it.
·A3/B3 and A3/B4 offer lower fuel economy but can provide better protection in some types of engine
C: Catalyst compatibility oils, suitable for passengers cars with exhaust treatment device. In this category there are five different classes:
·C1 and C2 offer better fuel economy due to the lower HTHS, C3 and C4 have higher HTHS
·C1 and C4 are low SAPS oils while C2 and C3 are mid SAPS oils.
·C5, which is the last introduced category, offer very high fuel economy due to the lower level of HTHS and needs to be used specifically in engines designed for it.
E: Heavy Duty Diesel engine oils, suitable for heavy duty engine. In this category there are four different classes.
·E4 and E6 offer longer drain interval while E7 and E9 offer medium drain interval
·E6 and E9 can be used in engines which require limited SAPS level including the Euro VI engines, while E4 and E7 present higher SAPS level and meet the requirements till Euro V engine.
SAPS is referred to the content of Sulphated Ash, Phosphorus, Sulphur, the content of SAPS is important for the compatibility with the exhaust after treatment device.
HTHS stands for High Temperature High Share which refers to how thin the oil film is in running conditions.
Are you interested in Eni lubricants? Contact us or one of our distributors, or subscribe to the Eni newsletter.