Choosing oil for a used engine

Refueling a high mileage engine with conventional oil bought at random is a big mistake that even experienced drivers make. Let's not scoff at the engines that have already seen the views and find out how the characteristics of the lubricant change during production, and which brands of engine oils are best suited for pouring into internal combustion engines with impressive mileage.

What is viscosity and what do you need to know about it?

One of the key characteristics of motor lubricant is viscosity. This term describes the resistance to shear between two adjacent layers of fluid. The parameter is inversely dependent on temperature: the higher it is, the less viscous and more liquid the product will be, and vice versa.

The resistance of the oil to temperature changes determines the viscosity index - a parameter according to which lubricants are divided into classes according to the international classification SAE J300.



Take a closer look at the oil canister in your garage or store, and you will certainly see combinations of numbers and symbols on it, for example, 5W-20, 5W-40 and others. It is this marking that shows the viscosity of the lubricant for the engine. Having deciphered it, you will learn the most important thing, namely:

• ✅ The first digit before the letter W is the low-temperature viscosity grade. The lower the number, the lower the temperature you will be able to start the engine without any problems.
  
• ✅ The second number after the hyphen is the high temperature class. The larger the value, the less viscous (more liquid) the lubricant will be when the motor reaches the operating temperature range
  

For example, 0W-20 and 5W-20 products are identical in high temperature class, but the first option is superior to the second, as it allows you to easily start the engine in severe frosts.

How exactly does the oil lose its properties?

Viscosity is a variable characteristic of engine oil. During the operation of the car, the lubricant gradually loses its original properties. This happens for a number of reasons:

• ? natural aging of the additives included in the composition - they last for a maximum of 2-3 years
  
• ? absorption of moisture from the surrounding air does not have the best effect on the structure
  
• ? fluid contamination with fuel and friction products, incl. metal shavings
  

Signs that indicate the need to change the oil include darkening of the liquid, the appearance of air bubbles, the loss of a pronounced sediment and a violation of uniformity.

The operation of the engine with low-quality and / or used oil leads to even greater consumption of the engine resource, especially if its mileage exceeds 100 thousand km. The old lubricant does not cope with its tasks properly, the viscosity changes and goes beyond the values ​​​​recommended by the engine manufacturer, which “finishes off” the power unit even more.

What kind of oil do older engines need?

For the old ones, we will consider engines with an honest mileage of more than 100 thousand km. They have a number of problems:

• ★ change in internal geometry as a result of natural wear
  
• ★ leakage of oil seals, seals and gaskets
  
• ★ a large amount of metal shavings in the "free float"
  

With an increase in engine mileage, it is recommended to gradually increase the upper temperature class of the lubricant. For example, if you previously filled with a 5W-30 product and the odometer number has already traveled 100 km, select 5W-40 fluid during the next change.



When choosing a lubricant, be sure to consider the manufacturer's recommendations and the season. Do not go beyond the range indicated in the engine manual, and make changes regarding viscosity grades gradually. In winter, fill in a thinner and more frost-resistant oil (with a lower first and second number in the marking), and in summer, on the contrary, use a thick liquid. This will give you a confident start.

The use of a thicker oil (for example, 5W-40 instead of 5W-30) in relation to an engine with high mileage can reduce the consumption of lubricating fluid for waste. This is especially important in the case of old motors, which, with increasing mileage, begin to “sin” more and more noticeably with a strong “zhor” of lubricant. High viscosity also reduces fogging of gaskets, oil seals.

Top 4 Used Engine Oils

Next, we will look at 4 proven engine oils of popular brands designed for use in an engine with high mileage. We do not recommend saving on a purchase, because otherwise you will have to spend much larger amounts on a major overhaul or replacement of the motor.

SHELL Helix HX7 10W-40

Semi-synthetic oil based on a mix of synthetic and mineral additives. Increases engine life, provides reliable protection against excessive wear even in the case of long-term vehicle operation in urban conditions unfavorable for the engine. Suitable for internal combustion engines on gasoline, diesel, biodiesel and gasoline-ethanol mixtures.



Depending on the batch, SHELL Helix HX7 is bottled in Russia or in the European Union. Judging by customer reviews, there is no fundamental difference, and the quality is equally good for both options. The product has more than 340 reviews on Yandex.Market with a rating of 4,8 points.

Castrol GTX 5W-40 A3 / B4

Slightly more expensive and less rated compared to the previous version. It is 100% synthetic, thanks to which it retains its properties during storage for up to 5 years, it perfectly protects the engine with high mileage, it has a wide range of approvals, including those from Renault and Volkswagen. It can be safely used to service both gasoline and diesel engines.



Before pouring liquid into the internal combustion engine, be sure to check the product for counterfeit through the official website of the manufacturer. Fakes, albeit quite rare, are found, and you can’t prevent counterfeit lubricant from getting into a used engine.

ENEOS Super Gasoline SL 10W-40

Semi-synthetic oil with a much less “loud” brand than the first two, but it does not get any worse from this. The manufacturer claims that the product increases the life of the engine and is suitable for a wide range of vehicles, which, in addition to cars, also includes minibuses, vans, SUVs, including those with turbocharged internal combustion engines.



The opinion of users about the product is purely positive. The only thing is that there are fakes, so if you decide to buy this particular oil, order it in a trusted store. Negative reviews are mainly associated with counterfeit products, which are many times worse than the original.

LUKOIL Lux SN/CF 5W-40

The rating is completed by a domestic premium product at an affordable price - about 500 rubles per liter bottle. This is a multigrade synthetic oil that is equally well suited for gasoline and diesel engines with mileage, including those equipped with a turbine. One of the advantages is the prevention of the appearance of high and low temperature deposits in the internal combustion engine.



By the number of positive reviews, LUKOIL Lux SN / CF 5W-40 grease is on one of the first lines of the Yandex.Market rating. From this we can conclude that this is a quality product. As in other cases, beware of fakes that can cause great harm to the motor.

Does it make sense to buy expensive oil?

It is a mistake to believe that since the engine is old and “carries out” its own, then you can fill it with anything and not spend a lot on lubrication. On the contrary, if you do not want to get into capital or a complete replacement of the motor in the very near future, take the choice of lubricant very seriously. It is better to overpay 500-1000 rubles for oil than tens of thousands for repairs.

Finally, remember - when choosing a lubricant, be guided not by the ratings and not by the advice of your neighbor in the garage. First of all, rely on the official recommendations of the engine and / or car manufacturer. You can find them both in the user manual and on the Internet.