How Often Should You Change Your Engine Oil?

How Often Should You Change Your Engine Oil? The lifespan of an engine depends on many factors. One of the most important, if not the most important, is the quality of the lubricant. Engine oil should not only be selected according to the vehicle manufacturer's recommendations, but also be in good condition. The oil change interval is crucial here. Over time and with the kilometres driven, the oil loses its original properties, not only its lubricating ones, but also its cooling ones. Older drivers or owners of youngtimers remember vehicles where the oil was changed every 8,000 to 10,000 km. In modern vehicles, on the other hand, you find oil change intervals of over 30,000 km. That is a big difference. Where does it come from? And does an oil that stays in the engine for 30,000 to 40,000 km still do its job reliably?

What Affects Engine Oil Wear? There are several reasons for the extension of oil change intervals. The first is technological progress in engine manufacturing. More precise manufacturing of the moving engine parts reduces friction between the components that work together. As a result, fewer metal particles and less abrasion are produced. The development of the petrochemical industry should not be forgotten either. Modern engine oils are more resistant to high loads than oils from a few or several decades ago. The third point is marketing: long service intervals look good in advertising materials and appear attractive to many customers. Practice shows, however, that recommended oil change intervals of 25,000 km or more only work for vehicles that are used very gently. Gentle use means, for example: ✔ long distances, ✔ steady speed, ✔ motorway or expressway, ✔ infrequent starting and stopping of the engine, ✔ little city traffic, ✔ few short trips. The situation is quite different for vehicles that are driven mainly in the city. Traffic jams, short trips, frequent starting and stopping, a sporty driving style or difficult off-road conditions significantly accelerate the ageing of engine oil.

How Often Should You Change Your Engine Oil? For modern engines, manufacturers often specify intervals of 25,000 to 35,000 km. In practice, however, it makes sense to take the way the vehicle is used into account. A rough guideline: 15,000 to 20,000 km For vehicles that mostly cover long distances, are rarely stopped and restarted, and usually run under steady conditions. 10,000 to 15,000 km For vehicles used both in city traffic and on longer journeys. For many everyday cars, this is a sensible range. 7,000 to 10,000 km For vehicles that are driven mainly or exclusively in the city, often stand in traffic jams or are equipped with a start-stop system. This range is also recommended for drivers who like to drive dynamically. 5,000 to 7,000 km For vehicles used in motorsport, including at amateur level. This short interval is also sensible for SUVs, pick-ups and 4x4 vehicles used under severe conditions.

LongLife Oils LongLife oils repeatedly spark discussion. Are they really worthwhile? And do they differ from normal engine oils? In theory, LongLife oils are supposed to enable mileages of 30,000 to 40,000 km without damage to the engine. That sounds very good, but in practice it is not always realistic. Of course, such oils have a different composition from standard oils. They contain more anti-oxidation additives and more detergent components. Whether that is always sufficient depends heavily on how the vehicle is used. Many manufacturer specifications state that engine oil should be changed after a certain mileage or after a certain period of time. Often it says: every X kilometres or once a year. For LongLife oils, it can sometimes be two years. This is an important point: engine oil ages not only through kilometres driven, but also through time. Even a car that is driven only a few thousand kilometres per year can have oil in the engine that has already partly lost its original properties. That is why, with low annual mileage, it makes sense to change the oil and oil filter once a year. This is a comparatively small effort considering how important oil is for the life of the engine. For fleet operators, LongLife oils can be economically attractive because they reduce maintenance costs and downtime. Private vehicle owners, however, should view such long intervals with caution, especially if the vehicle is used in city traffic or for short trips.

What Makes Engine Oil Age Faster? The engine is a complex system. The weakest link can have a major influence on all other components. A decisive role is played not only by a mechanical component or a worn seal, but also by the engine oil itself. Conversely, engine defects can also degrade the oil. For example, damaged injectors can introduce fuel into the oil and thereby dilute it. The most important factors affecting the condition of the oil include: ✔ driving style, ✔ short-distance driving, ✔ city traffic, ✔ frequent starting and stopping of the engine, ✔ high engine load, ✔ sporty driving, ✔ high temperatures, ✔ modern downsizing engines, ✔ fuel entering the oil, ✔ soot, deposits and metal abrasion. City traffic on short trips is particularly unfavourable. The engine often does not reach its proper operating temperature. The oil does not get warm enough, moisture and fuel residues evaporate less readily, and the oil ages faster. The most favourable conditions for the engine and oil are longer journeys at a steady speed, for example on the motorway or expressway.

Modern Downsizing Engines Put More Stress on the Oil The design of the engine also influences the condition of the oil. Modern downsizing engines often deliver higher output from a smaller displacement. This results in higher temperatures and higher loads than in older, less highly stressed engines. In addition, smaller engines often have a smaller amount of oil in the system. Less oil therefore has to do more work. This means the oil can heat up faster, become contaminated faster and age faster. With modern turbocharged engines in particular, high-quality, fresh oil is especially important. It lubricates not only the engine itself but also the turbocharger, which operates at very high temperatures.

Always Change the Oil Together with the Oil Filter Why should you always change engine oil together with the oil filter? The answer is simple: over time and with the kilometres driven, the filter element clogs up and loses its effectiveness. The main contaminants include metal particles produced by friction in the engine. In addition, soot, deposits and other residues collect in the filter. For practical reasons, the oil filter should always be changed together with the oil. Continuing to use the old filter is only an apparent saving. Otherwise, the contaminants from the old filter would get back into the new oil. A dirty or clogged filter works worse than a new one. This has a direct effect on the life of the engine.

What Does an Oil Filter Look Like? Classic oil filters usually have the shape of a cylindrical metal canister. The filter element is inside. Today, oil filters with a replaceable element are also becoming increasingly popular. In this case, the filter housing stays in the vehicle while only the filter element is replaced. During servicing, the housing should be cleaned and the old element replaced with a new one.

The Trap of Long Oil Change Intervals That oil change intervals that are too long can damage the engine is logical. But why, then, do manufacturers specify such long intervals? The answer is somewhat more complex. Today, vehicles usually come with a warranty that is limited both in time and by mileage. This limit is often around 100,000 to 150,000 km and 3 to 7 years, depending on the manufacturer and warranty terms. During the warranty period, vehicles that have their oil changed every 20,000 to 35,000 km according to the manufacturer's specifications do not always suffer serious engine damage right away. In practice, however, many modern engines can develop serious problems before or shortly after 200,000 km. By then the warranty has usually expired and the owner bears the repair costs. Private buyers in particular are often hit hard by this, while fleet vehicles are sold beforehand, once they reach higher mileages. Part of this early engine damage can be related to extended oil change intervals. That sounds complicated, but it is understandable: long intervals are attractive for costs, advertising and fleet operation, but not always optimal for the long-term durability of the engine.

Should You Mix Oils of Different Brands or Types? Mixing different oils also raises many questions. In principle, it is best to always use an oil that meets the specification required by the manufacturer. In an emergency, topping up is more important than continuing to drive with too low an oil level. Nevertheless, you should avoid permanently and constantly mixing different oils, viscosities or quality classes. The additive packages of oils can differ. For clean, long-term maintenance, it is better to stick with the appropriate oil type and regularly change it completely, together with the filter.

Summary: How Often Should You Change Your Engine Oil? Regardless of make or model, it makes sense to change engine oil more often than stated in some owner's manuals. The values given by the manufacturer can often be regarded as idealised conditions. In practice, however, conditions are frequently much harsher. In extreme cases, oil should even be changed three to four times more often than the manufacturer intends. This applies above all to vehicles used in city traffic, on short trips, in sporty driving or in heavy off-road use. For most vehicles, a safe compromise is: An oil change every 10,000 to 15,000 km or once a year, whichever comes first. LongLife oils are interesting mainly for fleet operators and less so for drivers who want to keep their vehicle for a long time. Engine oil plays too important a role in the engine to let it age for too long. Fresh, high-quality oil and a new oil filter are one of the simplest and cheapest ways to significantly extend the life of an engine.