There are several viscosity grades to choose from, and thinner motor oils are becoming increasingly popular. The OEM-recommended viscosity grades are the first item to think about. If your engine is stock, conform to the specifications that the engineers used while designing and developing it. Most engines will accept a variety of viscosity classes, allowing you to choose the one that best suits your equipment’s application. If your engine has been modified, knowing about it might help you make the best decision. Let’s take a closer look so this isn’t just a coin toss.
To begin, there are two forms of viscosity: kinematic and dynamic viscosity. The numbers we’re all familiar with on a container of oil are used to describe kinematic viscosity. A kinematic viscosity grade is usually made up of a single number (mono viscosity grade) or two numbers separated by a dash (multi viscosity grade). We’ll stick to the two-number approach because most heavy-duty oil has multi-viscosity. The cold temperature viscosity is represented by the first number on the left (15 in this case), which also bears the letter “W.” (which stands for winter, engineers are so creative). The kinematic viscosity at a standard engine operating temperature, usually 100 degrees C, is represented by the second number to the right (40 in this example). The thinner the oil, the lower the kinematic viscosity number. In frigid conditions, for example, a 5W-40 oil will be thinner than a 15W-40 oil, but at normal operating temperatures, both oils will flow the same. When comparing a 10W-30 to a 15W-40, the 10W-30 will be thinner at both low and high temperatures, with less resistance to flow. Keep in mind that corn syrup is high and corn liquor is low.
That’s kinematic viscosity in a nutshell. Let’s go on to the most recent API rating. How come CK oils have a different viscosity than FA oils, despite the fact that they are both 10W-30? Temperature, pressure, and the speed at which you shear it are all factors that influence viscosity (which relates to engine speed). We work mostly at atmospheric pressure or somewhat higher, so we can consider that a constant. The temperature rises from ambient to the regular working temperature of the engine, which is normally approximately 100 degrees Celsius. As a result, the most important variable is speed. The kinetic viscosity is measured at an extremely slow speed, with just gravity acting on it. The SAE grade is determined by three dynamic viscosity tests. Cold Cranking Viscosity, CCS, performed at high speed (shear), and Mini Rotary Viscosity, MRV, performed at low speed (shear). The High Temperature High Shear (HTHS) viscosity is the most frequent dynamic viscosity utilized to enhance fuel economy. We now have the technology in oil to adjust the viscosity so that it behaves differently when speed changes, which will aid us in meeting the demands of today’s sophisticated engines.
The choice is between lower viscosity to reduce pumping and shearing losses versus floating the crankshaft on a wedge of oil to protect it from hitting the bushings (the technical term is hydrodynamic lubrication.) Oil with a lower viscosity decreases parasitic losses, resulting in better fuel efficiency and power. Parasitic losses are items that put a strain on the engine’s power, similar to a parasite or a leach. Isn’t it a nice mental image now? Pumping and shearing viscosity is easier with lower viscosity. As a result, several heavy-duty lubricants are switching from 15W-40 to 10W-30. If the engine is designed and built to use a 10W-30 instead of a 15W-40, it can enhance fuel economy and power. The difference in pumping is easy to understand, but what about shearing oil? When the crank slides across the wedge of oil delivered by your oil pump inside the bearings, hydrodynamic lubrication is created. It takes more work to move something that is thicker. Consider tossing a baseball into the sea. The amount of work isn’t much different than doing it in air if you go through the action carefully (kinematic). However, as you try to throw it quicker, the force required increases at a greater pace than your arm’s speed (dynamic). Consider how much more difficult it would be in corn syrup than in water. Crankshafts and other moving engine parts must shear the oil, which is the same problem we see with parasitic losses in engines. And the less energy we waste, the slower it is sheared or the thinner the oil is. This is why heavy-duty engines’ cruising speeds have been steadily decreasing in order to reduce parasitic losses and increase fuel economy.
Power is influenced by the same elements that influence fuel economy. However, if the viscosity is reduced further, the oil will become too thin to prevent the crank from rubbing against the bushings during operation. Then the engine’s life and durability begin to deteriorate. To comprehend the required thickness, we must first learn about the Lambda ratio, which is a term used by engine designers. First, let’s look at the hardware. The viscosity of the oil, the area of the bushing touching the crankshaft, and the force pressing the connecting rod all influence the distance between the journal bearings and the crankshaft. The upper bushing on the connecting rod and the lower bushing in the main bearings are the first to show wear due to the piston’s loading through the connecting rod. The connecting rod tries to push the crankshaft out of the bottom of the block due to the combustion force.
Let’s take Lambda as a ratio of oil thickness, stress on the bushing, and asperity height to keep things simple. We’ve already specified all of those variables except asperity height, so let’s get started with that. Even highly smooth surfaces on machined objects are not that smooth when examined closely. It seems to reason that the rougher the surfaces, the more oil thickness is required to keep them from colliding. The less oil film we need to prevent rubbing, the smoother the crankshaft can be. Engine makers may be able to use thinner oils due to improvements in manufacturing procedures such as burnishing, polishing, and super finishing of crankshafts.
However, in order to improve fuel economy, engine designers increase cylinder pressure, which increases the stress on the connecting rod, making the oil coating thinner. Lowering the engine’s speed allows it to shear the oil more slowly, resulting in increased fuel economy and lower carbon emissions (Remember throwing the baseball underwater). At the same time that the engine is utilizing thinner oil for better fuel economy, the connecting rod is experiencing increased force, which in the past would have required heavier oil. This is made possible by advanced manufacturing techniques, and we collaborate closely with engine manufacturers to achieve the ideal combination of economy and durability.
Now, a brief note to all of you who have diesel engines with chips or high-performance upgrades. We would not advocate a lower viscosity oil because it raises cylinder pressures much above the manufacturer’s specified limits. If the adjustments you’ve made don’t involve improved surface finishing processes, you should at the very least give your bearings some 15W-40 love.
Going to a 10W-30 CK oil in a commercial fleet with good fuel economy is a positive move for fuel economy. If engine durability is more important to you, and you drive engines to the end of their useful lives, and a few percentage points of fuel economy isn’t a big deal, 15W-40 is the way to go. Choose the proper viscosity, and your engine will reward you by continuing to work.
Is 15W-40 oil reserved for diesel engines only?
ADVANTAGE Most manufacturers of diesel and gasoline engines demand 15W-40 HEAVY DUTY DIESEL ENGINE OIL to fulfill or exceed their warranty requirements. It’s made for older engines that run on higher sulfur fuels (500 ppm and above). ADVANTAGE 15W-40 HEAVY DUTY DIESEL ENGINE OIL is backward compatible with prior API Oil Categories and can be used in over-the-road diesel vehicles, off-highway diesel equipment, agricultural tractors, and passenger cars and light trucks with diesel, turbo-charged diesel engines, or gasoline engines.
How Is 5W-30 Oil Different From Other Engine Oils?
When compared to, say, 10W-30 oil, 5W-30 oil has a better low temperature viscosity grade. As a result, in freezing temperatures, the 5W-30 is less viscous.
Because of its low viscosity, this oil does not thicken at lower temperatures and flows freely through the engine without producing friction.
During the winter, the viscosity grade 5W-30 operates better than other lubricants, preventing car engine wear and tear (thanks to anti wear additives).
5W-30 oil can withstand temperatures up to 95 degrees Fahrenheit before switching to a higher viscosity high-temperature oil.
5W-30 oil is unsuitable for use in extremely high temperatures since car engines require a heavier oil with proper bearing support and cushioning at these temperatures. Because 5W-30 oil is thinner than other multigrade oils like 5W-40, it may not adequately lubricate the engine.
Is 5W-30 Oil Suited For Heavy-Duty Use?
In general, 5W-30 oil is suggested for use in gasoline and light-duty diesel engines.
However, in the right conditions, 5W-30 can be sufficient for heavy-duty use (colder temperatures).
Due to its great viscosity, it can tolerate any amount of cold temperature and mild pressure during the winter.
This viscosity grade oil should not be used in high-temperature, heavy-duty applications. This could lead to insufficient lubrication and cushioning under high pressure, lowering fuel efficiency and increasing oil consumption.
Is 5W-30 A Synthetic Oil?
Both traditional oil (commonly known as mineral oil) and synthetic motor oil are available in 5W-30.
To make SAE 5W-30 synthetic motor oil, petroleum molecules are broken down and rebuilt to generate refined base oil. Various additives are put to this for best engine protection and longevity.
5W-30 conventional motor oil, on the other hand, is made out of refined crude oil as its base oil. Anti-wear chemicals are added to this base oil.
Despite the fact that conventional and synthetic motor oils have identical characteristics, synthetic motor oil outperforms mineral oil.
In terms of oil viscosity grade 5W-30, new traditional motor oil will perform identically to 5W-30 synthetic oil. It will, however, deteriorate faster over time, affecting engine performance and fuel efficiency.
Synthetic oil, on the other hand, is more stable and provides superior engine protection, as well as lubricating crucial engine elements.
Note: After a certain point, engine oil (synthetic, traditional, or synthetic blend) degrades and loses its fuel efficiency.
Although some oils have a high viscosity by nature, you should be able to distinguish between thick oil and tainted oil. Dark, sludgy oil and engine deposits indicate that it’s time for an oil change, and they can shorten the life of your engine.
Is 5W-30 Oil Used In Diesel Engines?
The compression rate of a diesel engine is substantially higher than that of a gasoline engine. As a result, they require engine oils with a high viscosity or that are totally synthetic and can operate at high temperatures.
While lubricating your engine parts, the oil used in the motor should be able to endure a high operating temperature and pressure.
While 5W-30 oil is adequate for light-duty diesel engines, you should definitely choose a stronger, thicker oil for daily, heavy-duty use (e.g. 15W-40 engine oil).
What Are The Benefits Of Using 5W-30 Oil?
5W-30 oil is suitable for a wide range of vehicle and light truck engines. This multi-grade oil is very adaptable and covers a wide temperature range.
As a result, using 5W-30 (conventional or synthetic oil) has the following advantages:
- 5W-30 multigrade oil is ideal for cars that drive frequently in changing weather conditions. It can operate at temperatures as high as 95 degrees Fahrenheit and as low as nearly -22 degrees Fahrenheit.
- It also decreases the chances of thermal breakdown and extends the life of your car’s engine thanks to its low temperature viscosity grade.
- When compared to a thicker oil, it helps protect internal combustion engine parts and provides greater start-stop performance.
- It’s perfect for long-distance travels where a higher mileage oil with lower consumption rates is required.
- It’s suitable for an older engine because most older automobiles require a lightweight oil that doesn’t put too much strain on the engine.
Is it possible to use 5W-40 for diesel?
For modern diesel engines running in harsh environments, Mobil 1TM Turbo Diesel Truck 5W-40 full synthetic performance heavy-duty diesel engine oil helps extend engine life while delivering long drain capability and fuel economy benefits.
All super-high-performance diesel applications, including new low-emission engine designs with Exhaust Gas Recirculation, should use Mobil 1 Turbo Diesel Truck 5W-40 engine oil (EGR). These are some of the applications:
- Engines that operate in both high-speed/high-load and stop-and-go situations on the highway
- Engines for off-highway use that are subjected to extreme low-speed/heavy-load situations
- Almost all diesel-powered equipment produced by American, European, and Japanese manufacturers.
- Mixed fleets and high-performance gasoline engines
- Refrigeration equipment
Many low-emission diesel engines produce more soot and run at higher temperatures than previous engines. This boosts the demand for high-performance lubricants dramatically. Due to today’s tighter engine designs, there is less new oil makeup to restore depleted additives, resulting in less fresh oil makeup. Because the top piston rings are higher, the oil layer is closer to the combustion chamber, exposing the lubricant to severe heat stresses. Unlike other high-performance diesel engine oils, Mobil 1 Turbo Diesel Truck 5W-40 engine oil helps retain great performance at substantially higher temperatures. It’s also completely compatible with standard oils. Its capacity to drain for an extended period of time improves operational efficiency and lowers overall costs.
Please read our Mobil 1TM limited warranty for more information. Always refer to your owner’s manual for information on the manufacturer’s recommended oil viscosity grade, API service classification, and any builder approvals.
If your vehicle is still under warranty, stick to the oil-life sensor’s recommendations or the oil-change intervals indicated in your owner’s handbook. To guarantee effective operation, proper maintenance practices are essential, including monitoring the oil level on a regular basis to ensure the proper amount of oil is present.
Is 10W 40 oil suitable for diesel engines?
1 10W 40 grades are recommended for new generation diesel engines in heavy commercial, light commercial, and multi-utility vehicles that utilise Euro IV/III/II compliant technology such as turbocharging, CRDI, and EGR, among others.
Is it better to use 10w30 or 15W-40?
High-quality 10W-30 oils can work just as well as 15W-40 oils, if not better. The claimed viscosity of an HDEO is a viscosity within a range on the SAE viscosity scale, rather than an exact viscosity.
What happens if I substitute 10w30 for 15w40?
Because 10W-30 is thinner than 15W-40, it has a lower film strength and is more prone to oxidation. As a result, high-quality chemicals are required to compensate for those flaws, allowing 10W-30 to protect as well as 15W-40 and last as long.
What happens if 10w30 is used instead of 5w30?
It’s always a good idea to use the recommended weight of motor oil by the car’s manufacturer; using the proper oil will provide you the optimum fuel economy and protection. Because thick oil does not transfer heat as well as thin oil, using oil with a high viscosity might result in greater drag and high oil temperatures.
Using oil with a lower viscosity than required for your car, on the other hand, will cause the oil to fly off the internal parts when the vehicle is in motion.
This will eventually result in metal-on-metal contact, causing the engine components to wear out.
Q. Can I Mix 10w30 and 5w30?
Most oils will mix perfectly if they are synthetically similar. As a result, mixing 10w30 and 5w30 is not a problem because one will be topping up. The engine will not be affected by mixing the viscosity of the oils. Because the viscosity of 5w30 and 10w30 engine oils is similar, mixing them is not a bad idea.
Q. Is 10w30 thicker than 5w30?
Because it has a higher viscosity in low temperatures, 10w30 is thicker than 5w30. During the winter season, the engine oil will flow slower than 5w30. Metal oil with a higher viscosity seals better than oil with a lower viscosity. Motor and engine parts are better lubricated with thicker oil.
Q. Should I Use Thicker Oil In An Older Engine?
Yes, thick engine oil such as 10w30 should be used for older engines and motors. Oil pressure in older engines will be improved by using thick engine oil. This is due to the fact that as the engine ages, the clearances expand, requiring less liquid oil for better protection.
Q. Which is better, 5w30, or 10w30?
Both 10w30 and 5w30 engine oils are excellent choices. Understanding how each of them works in a specific environment is critical for optimal performance. 5wso is suitable for all seasons, providing optimal protection in both summer and winter. Because it creates low drag on bearings and moving components of the motor, this oil also gives a good level of fuel efficiency to the user. Because it is thicker, 10w30 has better sealing capabilities for older motors.