The most important factor to consider when choosing an oil for your engine parts is the viscosity (usually written in a format like 5W-30).
A vehicle owner’s manual is your best guide to selecting an engine oil.
The owner’s manual states:
- Defines the viscosity and type of engine oil that the car manufacturer recommends
- Details about cold or hot climates and seasonal use may be included
- Include alternative-weight oils if you can’t find the exact product needed
However, what can you do if the manual is missing?
Don’t freak out.
Answers still need to be found:
- If your engine has an oil-fill cap on top, you’ll find the viscosity rating there.
- There may be a small decal applied under the hood that indicates the viscosity grade needed.
- Check with your vehicle dealership for its engine oil recommendation.
- A parts store’s oil section sometimes has a chart listing which oil is best for certain vehicles.
- Oil companies provide online databases for finding the right oil for your vehicle’s make and model.
The final option is to consult a professional mechanic if all of the above fail to solve the problem.
Next, let’s discuss motor oil selection in more detail.
What Factors Influence My Choice of Motor Oil?
Here are some factors to consider when choosing your engine oil:
1. Viscosity of Engine Oil
Viscosity (or oil weight) is the most critical factor and is specified by a format like “5W-30.”
Oil’s viscosity represents its ability to flow at different temperatures.
Heat makes engine oil thinner and cooling makes it thicker.
In general, thicker oil provides a better lubricating film between the moving engine parts. Due to the excessive thickness, it may be difficult to crank the car, as the engine requires more energy to move its parts, reducing fuel economy.
Oil with a thinner consistency may flow better, but it may not provide enough protection for moving parts.
Adding additives to motor oils may reduce their tendency to thicken or thin with temperature changes. In addition to foam inhibitors, additives provide other benefits.
2. Seasons And Climate
Several different temperatures are covered by modern engine oils.
Certain oil grades perform better in certain situations, however.
A hotter climate might require an oil that resists excessive thinning (like 10W-40), while colder regions might require an oil that doesn’t thicken easily at lower temperatures (like 5W-30).
From summer to winter, you may also need to change your engine oil.
3. Conditions And Habits Of Driving
When driving in harsh conditions, like off-roading or towing, the motor oil must work harder, requiring more frequent oil changes. It might be necessary to use motor oil containing additives that help reduce friction under high temperatures and heavy loads.
Short trips under 15 minutes may not allow your engine to reach maximum operating temperature consistently, causing water condensation to not evaporate, resulting in sludge buildup. It may be necessary to use an engine oil that contains additives that prevent sludge formation in this case.
4. Age of the Engine
In cars with multi-valve, high-rev engines, thinner oil is typically required to prevent damage during start-up. An older engine in a classic ride, on the other hand, needs a thicker oil to ensure proper oil pressure between worn engine parts.
So now you know how to figure out what type of oil your car needs.
Let’s answer some FAQs.
Frequently Asked Questions
The following questions and answers pertain to engine oil use:
i) How Do Motor Oil Viscosity Ratings Work?
SAE’s (Society of Automotive Engineers) viscosity rating, or viscosity grade, is a measure of motor oil’s fluidity and performance at high and low temperatures. Typically, the format will be something like 5W-30.
Generally, the first number preceding the W (which stands for Winter) represents the oil’s thickness at 0OF (-17.8OC). Cold weather makes oil run more freely.
0W-20 can flow better at low temperatures than 10W-30, for example.
At running temperatures, the second number represents the oil’s characteristics and is usually rated around 212oF (100oC). The higher this second number, the harder it is for the oil to thin. At higher temperatures, 10W-40 is thicker than 10W-30.
Regardless of whether the oil is synthetic or traditional, viscosity ratings apply to both. Nowadays you’re most likely to find a 5W-30 or 10W-30 oil in your car.
ii) How Do Motor Oil Labels Work?
Generally, high-quality engine oils are labeled with the API icon and the API starburst symbol (American Petroleum Institute).
This is what the API donut should look like:
- Identifying the SAE viscosity rating (5W-30, 0W-20, etc.).
- A service designation on the container (letters like SN, SP, CK-4)
- An indication whether the oil has passed the Resource Conserving test
API’s latest service standards are “SP” for gasoline (petrol) engines and “CK-4” for diesel engines. Older engines may be fine with oil with an API service rating of “SG,” but newer cars may require oil with an API service rating of “SP.”
An API starburst symbol indicates the engine oil has passed the service tests listed in the API donut. Assuming an oil “meets” an API service standard isn’t the same as ensuring it’s actually registered and tested to prove compliance.
iii) What Types of Motor Oil Are There?
Motor oils are composed of a base oil and additives.
Engine oils are made up of 70%-90% base oils which are derived from crude oil or natural gas. Additional 10-30% are additives, which have several functions, including optimizing oil consumption and preventing corrosion in the engine.
On store shelves, you’ll usually find four types of motor oil:
a) Conventional Motor Oil
The cheapest type of engine oil is conventional motor oil, which is made of refined crude oil. Mineral oil is also known as organic oil or mineral oil. Light-duty newer cars with simple engines and low-to-average mileage are best suited to it.
Oil that is conventional degrades faster than other types, so it is recommended to change conventional oil every 4,000 miles or four months. Alternatively, if your vehicle has an oil-change indicator, follow its directions and be sure to change the oil filter as well.
b) Synthetic Motor Oil
In addition to higher viscosity levels, synthetic motor oils are resistant to thermal breakdown, oxidation, and sludge formation, improving fuel efficiency.
High-performance vehicles require high levels of lubrication, which synthetic oil provides. However, it can cost up to four times as much as conventional oil.
With its improved performance, you’ll still need to change your synthetic oil every 7,500-10,000 miles. Be sure to pay attention to your oil-change indicator or follow the manufacturer’s recommendations.
c) Synthetic Blend Motor Oil
The synthetic blend motor oil combines conventional oil with synthetic oil base stocks with some additives. It has many of the same characteristics as full synthetic oil, but is less expensive.
Synthetic blend oil might be a good choice if you are considering switching from conventional oil, but are deterred by the cost of full synthetic oil.
d) High Mileage Oil
A high mileage oil may be the right choice for your vehicle if it has logged more than 75,000 miles. Oil leakage and seepage issues are minimized and oil consumption is reduced with this oil.
High mileage motor oil can also help cut smoke and emissions in an older engine and can be made from conventional, synthetic blend, or full synthetic oil.
iv) Are different motor oils compatible with each other?
The answer is yes, but it wouldn’t be advisable.
In order to be compatible, API oil types must all be the same.
A regular oil (conventional oil) can be added to a synthetic oil without causing any problems. Nonetheless, mixing will reduce the benefits of additives in synthetic oils.
To maintain the maximum benefits of the better oil formulation, it’s best to avoid mixing car oil types.
v) What Should I Do If I Have To Mix Different Motor Oils?
Sometimes, the exact motor oil you need cannot be found.
To get started, follow these steps:
First, choose an oil made by the same company as the one in your car. Pick one that has the same API Donut certification, if possible.
Additionally, choose a product that has chemical characteristics similar to what’s in your vehicle’s engine.
As an example:
Let’s say your car’s oil is a regular oil with a viscosity of 20W-50, API SM, and you need to top it off. When added to 20W-50 oil in the car’s engine, 10W-40 would reduce the engine’s viscosity.
It’s not recommended except in an emergency, after which you’d need a full oil change.
Selecting the wrong oil could result in expensive engine repairs, as the wrong oil can affect your car’s performance. Consult the owner’s manual whenever possible, and make sure you change the oil regularly.
Also, if you can’t find a manual, then you can get the answers you want from a mechanic.