The Myths on Oil Viscosity Grades and Brands
A vehicle cannot work without engine oil. Engine oil lubricates the moving parts in an engine to ensure its prolonged lifespan and facilitate various processes. In emergencies, some car owners are fond of mixing different grades of engine oil.
The big question is, can you mix oil viscosities? Of course, the simple answer is yes, but there is more to it than that.
Motor vehicles operate on varying oil grades and viscosity. As a result, the oils operate uniquely in varied conditions. Motor oils have different grade ratings based on different factors.
These grade ratings determine their viscosity and performance in various weather. Some people mix different grades of engine oil due to a lack of their regular motor oil or to switch to another brand with a different grade. Therefore, is it possible to mix different grades of engine oil?
Mixing Two Engine Oil Viscosities
Engine oil viscosity refers to the oil and its performance at specific temperatures. For example, thin oils have low viscosity, ideal for cold temperatures, while thick oils have high viscosity levels, perfect for high temperatures.
Therefore, it is essential to consider where you intend to drive and its average weather when choosing the best motor oil for your engine.
According to the scale, the Society of Automotive Engineers developed, engine viscosity is denoted using ‘XW-XX,’ with W referring to winter and XW showing viscosity at 100°C. It also represents the resistance of oil to thinning at high temperatures.
Mixing two similar brands and types of oil but with different viscosities is not harmful to your engine as long as you do not mix them equally.
By combining them, you may not predict the exact viscosity of the resultant oil, but it will be useful in lubricating your engine’s moving parts.
Often, the mixing of two different oil viscosities occurs when drivers are on a long-distance drive and need to top up their motor oil. However, mixing two different oil viscosities is not recommended for an entire oil change interval.
Mixing Different Oil Grades Can You Mix 5w30 and 5w40
You are commonly known as mixing oil weights. You can mix oil weights to add oil to your car and have excess oil. However, older vehicles require a different viscosity than newer ones, so sticking to your manufacturer's recommended settings is advisable.
Many cars and trucks use multi-grade oil, such as 5w30 and 10w30. These oils can start your engine at cold and normal temperatures of about 210˚F without compromising your engine's efficiency. In addition, multi-grade oils become thinner in cold weather to adequately protect the engine as it warms up.
The first number in the viscosity grade shows low temperature; here, it is 5W and 10W. The other figure in the viscosity grade refers to the high-temperature rating (i.e., 30).
When deciding whether to mix these multi-grade oils, it is best to consider the temperatures of where you live and your engine’s age.
5W-30 oil is reliable in both low starting temperatures (30˚C) and hot summer temperatures (35˚C). This multi-grade oil creates less drag on the moving engine parts and bearings, hence its high fuel efficiency.
10w30 oil is much thicker than 5w30; therefore, it is better suited for older vehicles and trucks. In addition, this oil provides better sealing capabilities required by older engines, hence, better protection of the engine’s moving parts. This oil performs best at temperatures above 18˚C and below 30˚C.
Mixing Different Oil Brands
Mixing different engine oil brands because of topping up your oil level does not cause irreparable harm to your engine. Engine oil is made by different companies and has a different chemical makeup; thus, mixing two brands for an entire oil change interval is not recommended.
A closer examination of the top oil brands like Total, Castrol, or Shell will reveal that each uses special additives for marketing its products. Castrol Titanium, for example, comes with a special titanium technology that helps the oil maintain its viscosity even under extreme temperatures.
Each brand of engine oil has different additives with different roles. Therefore, mixing synthetic engine oil with regular oil may have limited or no effects. We have a great article on why you should consider using synthetic motor oil.
However, by combining two different brands of synthetic engine oil, the additives in both oils may react negatively, affecting your engine in the long run. Check your user manual for the best type of oil that is ideal for your vehicle.
Mixing Regular and Synthetic Motor Oils
Most of the time, you will find motorists mixing different oil types when you run low on oil, and at your next fuel station, you realize they do not have your usual motor oil.
The most common fear for any motorist is whether mixing oils will cause a gel-like substance. To eliminate your fears, first, note that natural and synthetic oils are made from the same basic compounds.
The only difference is that synthetic oil is more refined and contains many additives that can react with each other. These additives lead to the “gel” like substance you see in your car.
So if you are running low on oil, you should top up your car with the next available oil at the fuel station. Lacking engine oil is more disastrous than topping up with the wrong fuel. Motor oil is key in properly lubricating all your engine's movable parts.
If you run low on oil, you risk these movable parts grinding against each other, causing excessive friction and heat. If this continues, you will experience complete engine failure.
Motor oil also plays a vital role in heat dissipation. Cool oil is supplied to your engine from the oil pan, which cools some parts. This hot oil is then transported to the oil pan and cooled. This cycle helps in heat dissipation.
Note that you get some benefits from using expensive full synthetic oil. Manufacturers will have some expensive additives added to the oil to stabilize it.
You will have anti-wear agents, detergents, dispersants, anti-corrosive, and anti-oxidants. If you constantly mix your oils, you risk losing out on some of the benefits of expensive engine oil.
The Key difference between natural and conventional oil is refinement and distillation. Conventional oils are made from crude oil.
Synthetic oils have undergone more refinement, which means you have fewer carbon impurities. In addition, additives stabilize the oil, leaving you with a cleaner engine.
Signs that Your Oil Needs Changing
While most motor oils prescribe mileage before the next oil change, you must be on the lookout for when your oil becomes dirty and needs change. Here are some signs that you are running on bad oil.
Engine noise/knocking
Oil is vital for the lubrication of movable parts, but when you hear knocking sounds underneath your engine, know that the movable parts are knocking against each other, causing friction. If this persists, you may incur more in repairs.
Dark Motor Oil
Clean and normal oil is normally amber. As it circulates through the engine's movable parts, it picks up debris and other particles to form sludge. This leads to it having a dark color. You can check the oil color by removing the oil dipstick and checking it. Wipe it off before returning it to the engine for a proper checkup.
Check Engine Light Comes On
If you are running low on oil, the check engine light is one of the first lights that come on. While the light may symbolize several things, you must stop the car and check underneath your engine block for any signs of leakage. Next, check your engine oil levels and top up when necessary.
Strange Oil Smell Inside the Car
If your oil leaks into the combustion chambers, you will smell oil inside your car. This is dangerous; you should stop driving the car immediately and take it for a checkup.
Black or Dark Exhaust Smoke
It is normal to have whitish exhaust smoke – especially when driving in cold areas. This is usually because of water condensation and soon clears up as the engine warms up.
However, if you notice that the exhaust smoke is bluish, it could signal that your oil leaked into your combustion chambers.
An oil burnt smell will often accompany this. It would be best to have this checked immediately, as you will have less oil to lubricate moving parts.
Poor Fuel Economy
If your car runs on oil beyond the normal service level, it will form into sludge, making it harder for movable parts to operate. Since there is more strain on these parts, you consume more fuel.
Overheating: Oil is vital for keeping all your moving engine moving parts well lubricated. This reduces friction and helps in heat dissipation. If you run low on oil, these parts overheat because of friction. You notice that the engine temperature dials keep rising due to low oil.
Car Stalling
Your car can stall for various reasons, including spark plugs, battery, or stator problems. However, if your car runs out of oil, it could signal further engine problems, leading to your car stalling in the middle of the road.
It is prudent that whenever you notice a rise in engine temperature, you stop the car immediately, examine your oil levels and not drive until the issue you are facing is resolved.
Driving a car with low oil levels will worsen the lubrication between the moving parts, leading to metal grinding against each other. If this persists, you are looking at permanent engine failure.
What Happens to Your Car when You Use the Wrong Oil?
One of the key things you need to know about engine oil is that it is the engine's lifeblood. Without it, a car cannot operate efficiently. Therefore, motor oil first plays an important role in keeping all your movable parts well-lubricated.
When metallic parts are well lubricated, they do not grind against each other, hence causing friction. The oil acts as a thin layer of protection against this. As oil circulates through the engine, it takes excess heat and circulates it to the oil pan, where it is cooled.
Poor oil levels or dirty oil will reduce the viscosity of oil, preventing it from acting as an effective lubricant. Unfortunately, it will also continue damaging your engine parts because of sludge buildup.
For oil classification, the American Petroleum Institute (API) is the body mandated to regulate the use of motor oil in the country.
According to the classification, the “SN PLUS” category is for older and modern diesel engines; SN is for gasoline engines made before 2018, SM for gasoline engines built between 2011 and older, SL for 2004 and older, SJ for 2001 and older, SH cars built after 1996.
The list goes on, and you must check your car’s manufacturer manual for the correct classification. Motor oil operates differently under varying weather. Oil is harder to flow when it is extremely cold than during hotter seasons.
This can pose challenges when lifting a heavy load as oil works harder. For grading the viscosity of oil, you need to pay close attention to the labels on the oil container.
The “w” number on the container stands for winter and shows the thinness of the oil. If you live in an area receiving extreme cold temperatures, look for higher numbers. The second number denotes how oil behaves in hot weather. It shows how thick it becomes. The higher this number, the thicker the oil and its ability to keep its viscosity at high temperatures.
This means oil with a viscosity of 20 W-50 works better in extreme summers than 0W -20. Here are some crucial symptoms associated with the wrong motor oil.
Problems Starting Car in Cold Weather
If you live in a freezing area, you are familiar with the challenges of starting your car in the morning.
Oil thickens in cold weather, so it takes some time to warm up and lubricate your movable parts effectively. To mitigate this, ensure you get oil with the right viscosity number, i.e., the W should be higher for extremely cold places.
Oil leaks
Motor oil is often categorized based on the type of car it will be used for. Conventional oils are mostly preferred for older cars.
This oil has many additives that will clear sludge from old cars. They also prevent premature wear and tear. In addition, fully synthetic oils have undergone more distillation and refinement.
They also come with a significant amount of additives. Should you put full synthetic oil into an old car that is used to conventional oil, you notice the car has leaked oil.
This is because full synthetic oil can squeeze through tiny engine spaces. So while the oil leaks are minute, they may cause significant drops in oil levels and a burning smell.
The Strong Smell of Burning Oil
This normally happens for those drivers living in areas that are boiling. During high temperatures, if you have oil with the wrong viscosity number, it will break down, then evaporate or burn.
When oil burns, it loses its lubrication abilities, and you will experience engine overheating. If the problem is not solved immediately, some coolant hoses will start cracking, as they can’t handle the high engine temperatures.
A viscosity of 20W 50 is better than 20W 30 if you live in very hot places.
Poor Fuel Economy
If you make the mistake of purchasing a higher-viscosity oil for normal driving conditions, you will start seeing a spike in fuel consumption.
This is because the movable parts in your engine require more strength to operate, leading to more fuel consumption. Switch to a lower-viscosity oil when this happens.
Engine Ticking Noises
Oil is primarily used to lubricate the movable parts inside the engine. If oil is too thick, these metallic parts will start coming into contact.
The result is ticking noises from the engine. The noise is usually persistent as you start your car in cold weather, but it subsidizes as the oil warms up.
Mixing conventional and synthetic oil will not cause serious engine trouble; you lose out on the benefits of the more refined synthetic oil.
Full synthetic oil is more expensive, and it comes with a considerable amount of additives. On the other hand, it is also more refined than conventional oil, lacking the high carbon impurities in the latter.
Full synthetic oils are often used in modern engines, hence making the engines run efficiently. As a result, you should notice a considerable improvement in fuel economy once you use synthetic oil.
Oil also has fewer carbon emission footprints. The full synthetic oils, however, are more expensive hence the development of synthetic blends. These combine full synthetic oil and conventional oil.
You get the benefit of refined oil at an affordable price. If you are unsure which oil to use, consult your manufacturer's manual. Alternatively, ask your local mechanic for suggestions or a fuel attendant.
Conclusion
Good quality motor oil should efficiently lubricate moving parts in the engine and provide immense horsepower, thus prolonging its entire lifespan.
Motor oil manufacturers take a lot of time to balance out the chemicals in their products. Therefore, distorting this balance is not advisable, as it may not yield the desired results.
Luckily, even though you mix original oils, it does not cause any wear and damage to your engine, as long as the oils are similar.
Oils are miscible liquids, meaning you do not need to mix them in a particular proportion as they will easily mix.
However, it is best to stick to one grade of engine oil to avoid damaging your engine. Their unique additives may or may not be compatible. If not compatible, they are highly reactive, which is dangerous for your car.
FAQ
Will My Engine Break Down when I Combine Two Different Oil Brands Like Castrol and Shell?
It is unlikely anything terrible will happen when you mix two fresh oils. Engine oils combine synthetic and natural oils but may differ in additives.
These oils are highly compatible. By mixing two different engine oil, there is no production of unwanted byproducts; thus, engine performance will not have any immediate changes.
Car owners living in areas with extreme climatic changes usually switch from mineral to synthetic oil as the seasons change.
Mixing synthetic engine oil with regular oil may have limited or no effects. However, by combining two different brands of synthetic engine oil, the additives in both oils may react negatively, affecting your engine.
How Often Should I Change My Engine Oil?
Engines have changed a great deal in the last 20 years. Today, they are more efficient, demanding superior motor oil. Unfortunately, there are also more stringent environmental standards that have to be met to reduce carbon emissions.
The recommended period for an oil change is every 10,000 km. This can be sooner, depending on how you drive your car and whether you are experiencing leaks.
Normally, fully synthetic oils have a longer lifespan than conventional ones; some can even go for over 15,000 miles before the next oil change. However, constantly check your engine oil through the oil dipstick for the right viscosity and color.
Mixing engine oil will not be a disaster. But using one oil instead of a mixture ensures better viscosity. If possible, try using the recommended oil from the manufacturer for your car. If your car is a newer style, after, say, the year 2000, you should be safe to use synthetic oil and get better results from your engine.
However, synthetic oil is thinner and will find oil leaks if they are there, whereas thicker oil may not seep through these leaks.
