Oil in the engine is like blood in the human body. It plays a key role. Without it, the propulsion unit is unable to work properly. Too much oil is inadvisable, whereas too little of it may lead to failure. So, how much oil should you pour into the engine? How important is its role in the car and does it wear out?

How important is engine oil?

As said in the introduction, oil plays a key role in engine operation, whereas the lubrication system can be compared to the circulatory system in humans. Its proper operation guarantees longevity. Negligence in this respect may cause unpleasant consequences. Used, old or poor-quality oil may damage the lubrication system, whereas its shortage or excess inevitably leads to engine failure. Usually such failure is very costly, and in extreme cases it may even totally destroy the propulsion unit.

Despite appearances, engine oil fulfils multiple functions. Of course, the primary one is engine lubrication. This minimizes friction between all the working elements, i.e. pistons, valves, connecting rods etc. In addition, oil has cooling properties. Not only does the lack of oil increase friction between the parts, but also (as a result of the friction) raises temperature of the entire propulsion unit. Sometimes it only takes a shortage of oil (not necessarily a complete lack of it) to increase temperature and friction to such levels that they cause irreversible damage. The parts rubbing against one another are irreversibly deformed. It then becomes impossible to repair them and the only solution is to replace the damaged elements altogether.

For the reasons explained above, it is recommended to regularly replace oil and check its condition. While many people rely on a relevant indicator to inform them about an inadequate oil level in the engine, a far better solution is to take care of it on your own. It does not matter whether you have a luxury limousine or a compact city car, it should be every driver’s duty. So, how to check oil level in the engine?

How to check oil level in the engine?

While most young drivers had been acquainted with the procedure of checking oil level as part of their driving license courses and then the exams, not everyone remembers the individual steps. Each of these steps is important, though.

First of all, put the car on a flat surface. Any inclination, e.g. on the drive to the garage or car body inclination with two wheels on the pavement, may significantly distort the actual result. Also, note that the check should be conducted with a cool engine, e.g. a dozen or so minutes after switching it off. Checking the oil level with a hot engine may be dangerous. What is more, you should wait until the entire oil flows down to the oil sump.

The next step is to take out the measure (commonly referred to as “bayonet”) and carefully wipe it with a cloth or sponge to remove oil. Then insert the bayonet back to the same opening and again slowly take it out to check the position of the oil trace. The measure has two lines marking the minimum and maximum oil levels. It is best when the oil trace is roughly halfway between the lines. And what happens when the oil level comes close to or exceeds one of the lines?

Too much or too little – what does it mean?

As we said earlier, both too much and too little oil adversely affects the operation and longevity of the engine. If the oil level is lower than the minimum level on the measure, it may happen that a car which jumps up on a bump “swallows” a large amount of air, which will result in temporary operation without lubrication. If the oil level is very low and the engine operates in such conditions for a long time, its individual elements may be damaged and, in extreme cases, it may result in engine overheating or seizure.

Too much oil has a negative impact on gaskets. Once heated, its volume increases, putting pressure on all sealing elements. In addition, too much oil leads to excessive fuel consumption. Of course, oil shortage should be supplemented, which is far easier than draining the excess.

Amount of oil in the engine – how much to pour it?

Unfortunately, there is no universal solution or tip concerning the amount of oil which should be poured into the engine. It may be more than one litre for larger propulsion units and less than one litre for smaller ones. Typically it is one litre, but detailed information on a given propulsion unit can be found in the car’s manual.

It is worth pouring the oil in batches and then gradually refill it to achieve the optimum level, i.e. roughly halfway between the lines on the measure. Many experts claim that oil levels should be slightly different in the winter and summer. In winter, the oil level should be roughly one third of the distance between the lines. In such conditions the engine will heat to working temperature a bit faster. In summer, on the other hand, you should pour slightly more, i.e. roughly two thirds of the distance between the lines. The engine will then be better cooled even on hot days. However, you should be careful not to overfill oil. In such situation, you will need to drain it, which is not always possible in garage conditions.

How often should you check and refill oil?

The answer is plain and simple: as needed. If you use the car a lot, checking oil even once in a few days will not be too often. However, if you notice an oil spill under the car, you should perform the check every day and immediately go to a mechanic to remove the failure. If you suspect that the car “absorbs oil”, it is also worth checking the oil level more often and refill it as needed.

Neither is there a universal solution concerning refilling oil, as it should be done as needed to maintain the right level between the two lines. However, remember that you must not refill oil endlessly.  Do not forget to periodically change the entire oil in the engine!

The engine “absorbs” oil – should you worry?

It is worth knowing that every engine uses oil to a greater or lesser extent. It all depends on the car’s technical condition, mileage, or type of engine. Some older cars with high mileage can absorb as much as half a litre of oil per 1000 kilometres. Cars which are new and in full working order will not show oil consumption even after tens of thousands of kilometres. This does not mean, however, that you can forget about checking the oil level altogether.

Information about oil consumption can also be found in the car’s manual and it is a normal process. Typically, it is a few tenths of a litre per 1000 km, but these figures are in most cases overstated. Of course, if oil consumption is higher than indicated, or if, based on your own observations, something is wrong, it is worth checking the condition of the propulsion unit in the car service.

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