Automotive

The oil of the transmission is one of the components that we must monitor for the proper functioning of the engine system, so it will need preventive maintenance that may or may not entail a change of oil.

This detail must be looked up in the recommendation indicated by the manufacturer in the maintenance book and based on the type of transmission that they install, as there are different types (manual or automatic) and each has specific maintenance needs.

In general, we can say that:

· Synchronized or non-synchronized manual transmissions: oil in manual transmissions normally lasts for a lifetime, and is only changed when a repair is made to the transmission itself or because there are indications that the oil may be the cause of a malfunction. The main indications we can note are:

- Resistance of the system to changing gears in the cold.
- Continued resistance when changing gears.
- Grinding effect when changing gears.
- The gears slip once they are locked.

Automatic transmissions: depends on the type of transmission you have (DSG, VTC, PDK, etc.) and the type of use of the gearbox. Always follow the manufacturer's recommendations, although 60,000 km is generally considered ideal for an oil change. The clearest signs that alert us that our automatic transmission needs an oil change are:

- Slower gear changes.
- Excessive rpm drop when shifting up.
- Loss in the smoothness of gear shifting.

Given all the above, the oil of a transmission (automatic or manual) is subject to maintenance. In the event it needs to be changed, the type of transmission and the manufacturer's specifications must be taken into account, as the oils used are specific for each application and also its characteristics.

The answer to this question is yes, but this very resounding yes must be analyzed, identifying the causes that lead us to it.

All engines usually consume oil for greasing and cooling moving parts, so it is normal to add oil between two changes. This oil consumption may be variable and depends on the technology used by the manufacturer, as well as the type of use of our vehicle (normal, sports, city, intercity, etc.).

When we put more oil into our car, we do it because we have detected through a routine check that the level in the sump has fallen, because we have seen some oil slick on the floor of our parking spot or because the computer on board our vehicle informs us of a low level of oil.

1. Before replenishing oil, we must check in the maintenance manual or recommendation made by the manufacturer of the engine; in other words, we must be clear what type or quality of oil our vehicle uses (mineral or synthetic), which viscosity grade is to be used (5W30, 10W40) and which associated specifications must be met (ACEA/API or as specified by the manufacturer).

This simple check is essential and can save us unwanted visits to the garage to solve problems caused by a poor choice of oil to replenish.

Information to take into account:

Mixing different types of oils: Automotive lubricants are either mineral or synthetic, but they do not usually display any problems of miscibility or compatibility, but mixing different types of lubricants in the engine is not advisable since certain characteristics of the lubricant can be affected, not complying with the minimum lubrication requirements or protection of the system.

Topping up with different viscosity grade: Variations can normally be made in the lubricant used provided that the range of viscosities recommended by the manufacturer is followed. Beyond this, the use of unrecommended viscosities may cause internal wear due to friction and/or lack of lubricant film, as well as help raise the operating temperature of the overall engine by decreasing the efficiency of the cooling system.

Mixing lubricants of different qualities: On the market you will find lubricants with different additive technologies. In general this should not be a problem, but there is a case where it is necessary to be particularly careful, which is lubricants for vehicles with a diesel particulate filter (DPF/GPF). There are certain technologies for lubricants that damage those systems. This data must be taken into account when the lubricant is mixed, which must always be in line with the lubricant profiles specified by the manufacturer.

The type of lubricant or quality that your vehicle needs must be identified in the maintenance manual of the vehicle and defined by the specification of the manufacturers (VAG, MB, FORD, OPEL, BMW, RENAULT, PSA, etc.). This is undoubtedly the most important aspect when selecting the type of oil. These specifications define the viscosity grade to use (0W30, 5W30, 5W40) depending on the service conditions and the ambient temperature or environment (AT > -15ºC, -20°C, etc.).

By the ACEA (European Automobile Manufacturers Association) quality level, taking into account the following classification:

- ACEA A/B: applied in light Gasoline (A) and Diesel (B) vehicles.

- ACEA C: applied in light Gasoline and Diesel vehicles and gas post-treatment systems (DPF or GPF).

- ACEA E, applied in heavy vehicles (trucks, buses, public work machinery and some light vehicles, delivery trucks).

According to the API (American Petroleum Institute) quality level

API S/C: for use in gasoline (S) and heavy diesel (C) vehicles.

When in doubt, you can always check our lubrication guide at https://www.cepsa.es/es/utilidades/catalogo/guia

European automotive manufacturers have their own regulations or specifications tailored to each brand's needs. The manufacturer's specification takes precedence over any kind of ACEA quality level, although there is usually a correlation between the manufacturer's specification and the ACEA standard.

Asian manufacturers, however, have entered the European market without their own specification, so they are governed by ACEA, which will be the valid specification when claiming a warranty.

American manufacturers work very similarly to Europeans; they have their own manufacturer specifications but linked to the API regulations, which are the most widely used in both the US and Latin America.

The above is based on the owner's availability of the Vehicle Maintenance Book or Manual. Where this tool is not available, Cepsa has a lubricant guide that enables you to check the type of lubricant your vehicle uses in a quick and simple way, by simply indicating the type of vehicle, model and year of manufacture. See it at https://www.cepsa.es/es/utilidades/catalogo/guia

The viscosity of a car lubricant is a parameter established by the engine manufacturer (which does not have to be the same as that of the car). In the owner's manual of the car you will find that depending on certain parameters, it is permitted to use a smaller or larger range of viscosities. Within those parameters, you will find factors like weather conditions, fuel economy, and the lubricant adaptation to certain systems like the start-stop, among others. Let's discuss each of them a little:

- Weather conditions: The natural behavior of viscosity is to decrease as temperatures increase and to thicken as temperatures decrease. For this reason, to obtain the appropriate viscosity that creates protection for the system, the viscosity must be adjusted to the temperature of the environment. That is, the appropriate viscosity of a vehicle in Stockholm should be lighter than the viscosity used for a vehicle in Spain. The viscosity of the oil is specified in the vehicle manual according to temperature.

- Fuel economy: Within the range of options offered by the manufacturer, you will find more fuel economy than others, which allows the vehicle to function without damaging the engine. The lower viscosities cause less friction between moving parts, which reduces the amount of fuel needed to move the parts of the engine.

- Start-Stop systems: Vehicles incorporating such systems also allow slight viscosity changes to the lubricant. Usually manufacturers recommend light grades to avoid any wear every time the car starts, but slight viscosity increases are also permitted as a manual to adapt to the service conditions and climatology of the area.

In addition to these factors that are reflected in the vehicle manual, there is another important factor in changing viscosity, which is the age of the system. It is normal that over the years, there would be wear and tear of the engine through normal use and that the tolerances and clearances of the engine parts would increase. In order to create an airtight seal in the combustion chamber and thus increase efficiency in combustion, the viscosity of the oil must progressively be increased to create the necessary sealing conditions in the engine. The usual thing to do is to start to increase the viscosity grade of the oil when the vehicle starts to have an atypical consumption.

This can also be done in the case of oil consumption in new cars, but in this case the viscosity changes should be considerably more stringent than for vehicles of a certain age. It is important always to ensure that the option chosen to increase viscosity is one of the lubricants listed in the vehicle manual, since the vehicles are normally under warranty and the choice of a lubricant outside the suitable oils for that engine can invalidate the warranty.

This information can always be found in the vehicle manual, but if you don't have it to hand, here we give you recommendations of how to guess the capacity of the sump depending on different factors.

Obviously, not all cars have the same sump capacity, because it will depend on factors such as the system's cylinder capacity and cooling capacity, but usually the volume is between 4 liters and 5 liters. This is why the most common container sold for this application is 5 liters of capacity.

To date, larger vehicles with greater displacement and power had bigger sumps than those with more limited power. The evolution of engines on the market to ensure compliance with environmental emissions law has set engine development in the opposite direction, that is, increasingly powerful engines with smaller sumps. That is why the trend is to switch from 5-liter sumps to 4-liter sumps for these new, overloaded engines.

You will also find that the system's cooling capacity is an influencing factor. The thing about the cooling temperature is this: if an engine cools well, it will be possible to operate with fewer liters of oil than one that cools worse, since the oil degradation with temperature requires a higher degree of renewal.

Other factors that we need to take into account when looking at the capacity of the sump are the maximum and minimum levels of oil. Normally there is a variation of between 0.5 liters and 1 liter between the maximum and minimum mark, about 20% of the oil sump. It seems logical to think that, with 20% more oil in the sump, the lubricant properties would be conserved for longer since the heat stress to which the load is subject is more distributed and therefore has less impact on the degradation of the oil.

ACEA is an organization that governs the standards to be followed in the automotive world. ACEA (European Automobile Manufacturers’ Association) regulates standards in Europe ACEA, unlike API, which regulates American engines.

As its name suggests, the ACEA is the association of the main European car manufacturers.

This association publishes different specifications on the market that contain the necessary tests that the lubricant must meet to ensure the integrity of the system and its peripherals.

Within the ACEA specifications there are several classes depending on the type of vehicle, and within these classes, depending on the application and technological level of the oil. Finally, you can find the year of the ACEA that tells us the severity of the tests required by the specification. This type of test is updated every 4 years, making variations dependent on technological developments on the market.

- ACEA classes

A/B: Classes A and B are ACEAs specified for light diesel and gasoline vehicles without a particle filter.

C: Class C refers to light gasoline and diesel vehicles with a particle filter.

E: Class E is focused on heavy vehicles.

With the introduction of the new ACEA 2016, this distribution in light vehicles has changed, the ACEA A1/B1 is disappearing and the new category called ACEA C5, which is the mirror category of ACEA C3, but with an extra fuel economy category, is being introduced.

The American Petroleum Institute regulates the quality standards of automotive oil, and this association is more closely linked to American engine units, but is widely used throughout Asia and South America.

Unlike the ACEA, the API standards are much simpler, since they only have 2 classes, one for diesel and one for gasoline. Another factor that facilitates this classification is that the last specification launched is completely backward compatible with the remaining API market specifications within the same category. If, for example, I have a lubricant that says API CJ-4, I can use it on all those diesel engine units that require previous API specifications, CI-4, CH-4, etc.

API has 2 categories:

- Class C, for diesel engine units.

- Class S, for gasoline engine units.

Like the ACEA, the API launches updates to its categories and recently introduced two new categories for diesel vehicle, API CK-4 and FA-4 API. API CK-4 VA is on the development line of API CJ-4 and API FA-4, which is the first specification of the fuel economizer and not backward compatible with the remaining API specifications for diesel.

Viscosity is the most important property of an oil and almost all oils are classified using it. Engine oils are classified through their SAE grade, which is what the numbers and letters allocated to them mean.

To do this, we have to divide the SAE grade into two parts: the first number that accompanies the letter and represents the winter grades and a second number, always higher than the first, representing the summer grades.

The first number, which accompanies the W (Winter), tells us about the fluidity of the oil in the cold. The lower this number, the better the flow in the cold, and the oil will reach all parts of the engine and will thus ensure the protection of all components in less time.

The second number represents the summer grade. The higher the number, the greater the viscosity, and therefore the greater the lubricant film that will remain. The lubricant film results in greater protection of mechanical components and in a more watertight way. However, too thick a film also leads to increased fuel consumption and an increase in temperature by the very friction with such a viscous oil.

To measure a winter grade, the viscosity when pumping is fixed at 60,000 cP and you see how much the temperature can be lowered to have that viscosity. Depending on the value, it will be one grade or another:

Winter SAE grade: 5 W; temperature at which I have 60000 cP when pumping -35ºC
Winter SAE GRADE: 10 W; temperature at which I have 60000 cP when pumping -30ºC
Winter SAE GRADE: 15 W; temperature at which I have 60000 cP when pumping -25ºC
Winter SAE GRADE: 20 W; temperature at which I have 60000 cP when pumping -20ºC

To classify a summer grade, its viscosity at 100ºC is measured in centistokes (cSt) and depending on its value, it will have one number or another:

Summer SAE grade: 30; viscosity at 100ºC: 9.3 - 12.5 cSt
Summer SAE GRADE: 40; viscosity at 100ºC: 12.5 - 16.3 cSt
Summer SAE GRADE: 50; viscosity at 100ºC: 16.3 - 21.9 cSt
Summer SAE GRADE: 60; viscosity at 100ºC: 21.9 - 26.1 cSt

All oils on the market, whether mineral, synthetic or for gasoline or diesel engines, can be mixed together. However, the mixing of two qualities of different oils lowers the quality of the higher one.

The most suitable viscosity of a lubricant is what is recommended by the engine manufacturer.

Adapting the viscosity may be required according to the conditions of use of the vehicle, environment and climatic conditions. It should always be done under the supervision and recommendation of a lubrication specialist.

Yes, you can mix them in an emergency, like filling up when the oil level is low. It should be borne in mind that the resulting viscosity will not be optimal.

The interval between two oil changes is determined by the manufacturer according to the technical performance of the lubricant and engine characteristics. Generally, oil change depends on two parameters: mileage and time of use.

However, under certain conditions of use such as urban driving, with frequent starts and stops, it is important that the interval between oil changes be reduced. Whatever the conditions of use are, it is important to change the oil at least once a year.

In general, if the period between oil changes is long or for very intensive usage, you must replace the filter as well. Otherwise, you can change the filter every two changes of oil. We always recommend that you take the advice of the manufacturer or a good professional.

Yes. Oil must lubricate very critical parts, such as areas between the piston, the liner and the valves. Part of the lubricant film burns during the combustion process. Over time, the clearances are greater because of normal wear and tear on the engine parts, and the lubricant usage increases.

No. When exercising its lubrication function, the oil is subjected to multiple forces. In particular, it gathers impurities, and combustion and oxidation residues. The oil degrades and becomes less efficient. Once its lifetime is exceeded, its qualities alter and no longer guarantee the protection of the components of the engine, so it is necessary to replace the oil load regularly. Periodic topping up does not bring used oil up to standard.

No. Cleanliness of the internal parts of the engine is one of the functions of lubricant. In the combustion process of the engine, soot, lacquers and other impurities are generated. The lubricant must collect these impurities, and therefore it must darken.

Oil is the protector of the engine to avoid excessive wear and to neutralize acid from combustion. As such, it is essential that it is in good condition to fulfill its function.

The change period is a parameter established by the engine manufacturer according to its design parameters and field tests. There are also European and American standards that serve as the basis for many of the specifications that manufacturers require of the oils that are going to go into their engines.

Engine manufacturers mark the period of change by a concrete specification. For example, if an engine requires the oil lubricating it to comply with the VW 504.00/507.00 regulation and the oil that we put in the engine to be compliant as well, this indicates that the period of change is 30,000 km in ideal conditions since the oil has had to meet parameters to claim that it meets that specification.

This period of change established by manufacturers may vary depending on the operating conditions of the engine that can change it, like the type of driving, urban driving, climatic conditions such as humidity or atmospheric dust.

For instance, the engine of a delivery truck or a taxi will need an oil change before a vehicle used for long journeys due to the type of driving; a car in the Canary Islands will also have shorter change intervals compared to a motorcycle in Madrid due to weather conditions.

In other vehicles, like some older ones, they only require that the oil that lubricates the engine meet one of the European or American standards and indicates the period of change of the oil.

The oil level needs to be reviewed every so often to avoid greater evils, although most vehicles carry a sensor to tell us if the oil level is low in the sump. As a rule, if you do not have the vehicle manual or you cannot access the manufacturer's recommendations, the oil change periods for cars are generally as follows:

Change of synthetic oil and filter: one year or 15,000 km.
Change of semi-synthetic oil and filter: one year or 10,000 km.
Change of mineral oil and filter: one year or 5,000 km.

Remember to always follow the advice of your trusted garage. Our lubrication guide can help you!

STOU (Super Tractor Oils Universal) corresponds to a classification of integral multipurpose oils for tractors. It is reflected in oils valid for diesel engines, transmissions, end controls, wet brakes, gearboxes, differentials and hydraulics.

UTTO (Universal Transmissions Tractor Oil) corresponds to a multipurpose oil classification, valid for any part except engines. That is, oils for transmissions, hydraulic systems and wet brakes.

Motorcycle oils offer better oxidation and stability. In addition, there is generally only one oil in a motorcycle, as opposed to a car (transmission, engine, etc.), so it must meet the lubrication requirements for the engine, transmission and clutch. There are three reasons for these oils to have these characteristics:
- The sump of a motorcycle is approximately half the size of that of a car, so less oil is needed to lubricate all the mechanical parts (and the additive reserve, as there is less volume, will be less).
- Motorcycle engines rev up to twice the speed of vehicles. This makes it critical to have an oil specifically formulated for engines with these characteristics.
- For each liter of displacement, a motorcycle produces twice as much horsepower as a car, on average. This, again, means that the formulation of motorcycle oils must be special.

In the motorcycle, as there is only one oil for all the engine components, there are different cases. The engine requires an oil with low friction, low ash so as not to damage the exhaust catalyst. On the other hand, the transmission requires anti-wear and extreme pressure additives, which implies an increase in ash. Finally, the wet clutch is lubricated and needs some friction, so anti-friction additives incorporated in certain oils with fuel-saving properties for cars would not be suitable.

Finding the balance in the triangle of requirements is the key to formulating motorcycle oils.

Shear stability is the ability of the oil not to break down its chemical structure when subjected to high stresses. Unlike cars, this is a very important property, because motorcycle oil lubricates the transmission as well as the engine. Very extreme metal-to-metal contacts occur in the transmission, and these can cause the oil structure to "shear" and break its structure, losing its viscosity properties.

At the same displacement, a 2-stroke engine produces more power than a 4-stroke engine. This is because, over a given period of time, in 2-stroke there are more explosions than in a 4-stroke.

In 2-stroke engines, the fuel mixture entering the engine is accompanied by lubricating oil, which greases the moving parts of the combustion chamber and burns. The result of combustion is formed by gases from the burned fuel and oil, whose molecular chains are more complex. This means that, at the exhaust outlet, the gas is more polluting than that produced in a 4-stroke engine, where the amount of oil burned is minimal.

Acid formations are more common in outboard oils due to the marine environment in which they are usually found. That’s why anti-corrosion additives are enhanced in the additivation of these products.

The turbocharger is a mechanical element that maximizes the air-to-fuel ratio in the engine. The energy that rotates this component comes from the exhaust gases of the engine, where a turbine moves a shaft attached to the blades of a compressor.

This spinning motion reaches speeds of more than 150,000 revolutions per minute, and the temperature of the exhaust smoke exceeds 500ºC. This makes lubrication of its moving parts essential to prevent mechanical failure.

The main causes of turbocharger failure are threefold: inadequate oil, lubricant contamination and lack of lubrication. Due to the speed and temperature to which the equipment is subjected, critical parts need to be constantly bathed in oil, and if the oil contains impurities or does not arrive with the necessary continuity, there is a high risk of mechanical failure.

- If the lubricant used does not have sufficient resistance to extreme temperatures, the oil passing through the turbocharger may carbonize. This affects the rest of the piping and oil passages in the lubrication system, causing intermittent operation.
- Driving a cold engine at high speeds for short periods of time with an inadequate lubricant can cause momentary lubrication shortages in critical areas of the turbocharger, breaking the oil film and causing wear damage.
- A lubricant with too low a detergency/dispersancy level causes dirt particles to block the oil supply line to the turbocharger, limiting turbocharger lubrication.
- A lubricant whose change interval is not respected may contain dirt, water, fuel, combustion residues and wear particles. All these components reach the turbocharger oil circuit, causing a high level of wear.
- Lubricants with excessively high viscosities present fluidity limitations for pumping, leading to intermittent lubrication in key equipment parts. Given the speeds at which a turbocharger rotates, momentary absences of lubricant in sensitive areas can cause severe damage to the equipment.

Friction caused by a lubrication problem can damage bearings and insulating segments, leading to insulation failure and oil leakage into the turbine or compressor side. In addition, if the oil is contaminated, it will cause damage to these components due to the friction caused by the metal particles. So, it is important to choose a lubricant with high detergent power and a suitable viscosity grade.

In addition, wear on the bearings can cause play between the bearings and the turbocharger shaft, leading to improper movement where the compressor or turbine blades can come into contact with the equipment housing while in motion. The effects of metal-to-metal contact at these speeds are devastating to the blades, and their performance can be highly affected.

The change intervals and the oil filter are differential elements to prevent the turbocharger failures mentioned. Monitoring the oil through analysis techniques is an option widely used in large fleets. The objective is to promote preventive, predictive and corrective maintenance in their vehicles.

These lubricants are specifically designed for vehicles that include particulate filters as exhaust gas treatment systems, and they must have a suitable composition to make them compatible with this type of device. Ashes are usually additives that improve the protective properties of the lubricant, which come from the additives in the lubricant. Reducing ash can compromise the effectiveness of the lubricant, so choose only products whose protection technology is sufficient to respect the particulate filter and prevent wear at the same time.

This is an exhaust gas treatment system that reduces the emission of particulate matter into the atmosphere, especially soot produced in the combustion of diesel vehicles (DPF) or the latest gasoline models (GPF). This filter can be deteriorated by the use of unsuitable oils.

The DCT or dual clutch transmission uses two separate clutches, one for even speeds and one for odd speeds. The main feature of this equipment is that each change can be made without interrupting the transmission of power to the engine, since while one clutch produces power, the other can be engaged while the previous one is released.

The CVT or continuously variable transmission consists of two conical pulleys, linked by a drive belt. Depending on the speed and load of the engine, the shaft of the conical pulleys moves and the width of the pulley groove changes. This causes the belt to shift on the pulley, changing the power transmission between the motor and the transmission.

API GL-4 and GL5 are specifications for transmissions and differential groups (gears). The main difference is the content in the extreme pressure additivation. Oils for manual transmissions are usually of the API GL-4 type, while for axle and differential oils they are of the API GL-5 type, with a higher presence of EP additivation. However, GL-5 oils should not be used for manual transmissions when the manufacturer recommends GL-4. The reason is that the gearbox synchronizer is usually made of bronze, and GL-5 oils are reactive with this type of metal (due to their higher content of extreme pressure additives).