Looks like you need an engine oil top-up.
Should be pretty straightforward, right?
However, you’ve no idea what engine oil type or viscosity rating you need.
You’re probably asking yourself, “What oil does my car take?”
Or maybe, “Can I mix motor oil types?”
Don’t worry.
We’ll do our best to help you determine the right oil for your vehicle’s engine.
This Article Contains
- What Oil Does My Car Take?
- Does My Car Need Regular or Synthetic Oil?
- What Are Motor Oil Types?
- What Factors to Consider for Motor Oil Selection?
- 5 Engine Oil FAQs
What Oil Does My Car Take?
When picking an oil for your engine parts, the most important thing to consider is the oil’s viscosity (usually written in a format like 5W-30). Your best guide to selecting an engine oil is the vehicle owner’s manual, which:
- Will define the manufacturer’s recommended oil viscosity and type
- May include details for cold or hot climates and seasonal use
- May include alternative-weight oils if you can’t get hold of the exact product needed
But what can you do if the manual is missing?
Don’t panic.
There are still answers to be found:
- The oil filler cap on top of your engine may list the viscosity rating.
- The car manufacturer may apply a small decal under the hood, noting the viscosity grade needed.
- You can check with your vehicle dealership for a recommendation on engine oil.
- The oil section in a parts store sometimes has a chart listing vehicle makes and models and the right oil for them.
- Some oil companies offer online databases to search for the right oil for your vehicle’s make and model.
And if all these don’t yield any answers, you can still consult a professional mechanic for help.
So, say you know the viscosity needed.
But what about the oil type?
Does My Car Need Regular or Synthetic Oil?
Your owner’s manual should spell out the oil type. But if it doesn’t or if you’ve lost it, as a general rule:
- Conventional oils are the minimum standard for naturally aspirated engines. However, for better protection, you can use semi-synthetic or full-synthetic oils.
- For high-performance engines or those with turbochargers or superchargers, synthetic blends or full-synthetic oils are usually needed. Conventional oils won’t offer sufficient protection for these engines.
Let’s take a closer look at oil types.
What Are Motor Oil Types?
Motor oils are made of a base oil and additives.
The base oil is extracted from crude oil or natural gas and typically makes up 70-90% of engine oil. The remaining 10-30% are additives, which perform several functions, including optimizing oil consumption and keeping the car’s engine corrosion-free.
You’ll typically find four types of motor oil on store shelves:
A. Conventional Motor Oil
Conventional motor oil is a product of refined crude oil and is the cheapest type of engine oil. It’s also referred to as mineral oil or organic oil. It’s suited to light-duty newer cars with simple engines and low to average mileage.
Conventional oil degrades faster than other types, so getting a conventional oil change every 4,000 miles or 4 months is advisable. If your vehicle has an oil-change indicator, follow its guidance, and don’t forget to change the oil filter, too.
B. Full Synthetic Motor Oil
Full synthetic motor oil provides higher viscosity levels, is resistant to thermal breakdown, oxidation, and oil sludge formation, with improved fuel efficiency. Synthetic oil works for high-performance vehicles that demand high levels of lubrication. However, it can cost 2-4 times more than conventional oil.
Even with its improved performance, you’ll still need a synthetic oil change, usually within 7,500-10,000 miles. Pay attention to your oil-change indicator or follow the manufacturer’s recommendation.
C. Synthetic Blend Oil
Synthetic blend motor oil combines conventional oil with synthetic oil base stocks with some additives. It has many full synthetic oil characteristics but is lower priced.
If you’ve been thinking of switching from conventional oil for better protection but are deterred by the price of full synthetic oil, then a synthetic blend oil might be a good option.
D. High Mileage Oil
If your vehicle has clocked over 75,000 miles, high mileage motor oil might be the oil for you. This oil is designed to reduce oil consumption and minimize oil leak and seepage issues. High mileage oil can also help cut smoke and emissions in older engines and can be formulated from conventional, synthetic blends or full synthetic motor oil.
Next, let’s get into some detail regarding motor oil selection.
What Factors to Consider for Motor Oil Selection?
Here’s a look at some elements to consider when picking out the right motor oil:
1. Engine Oil Viscosity
Engine oil viscosity (or weight) is the most crucial factor and has a format like “5W-30.”
Viscosity represents an oil’s ability to flow at different temperatures. Engine oil becomes thinner when it heats up and thickens as it cools.
Thicker oil generally provides a better lubricating film between the engine’s moving parts. However, the excessive thickness can make it hard to crank the car as the engine needs more energy to move its parts, reducing fuel economy. Thinner oil may flow better but might not offer enough protection for vital moving components.
Motor oils may have additives to reduce their tendency to thicken or thin with changing temperatures. Additives also provide other features like foam inhibitors.
2. Engine Fuel Type
Diesel and gasoline engines often have different additives because they work differently. Diesel engines produce soot that gasoline engines don’t. Using motor oil designed for diesel engines in gasoline engines could have severe effects on their catalytic converters, for example.
So, it’s best to use a motor oil formulated for your specific engine fuel type, though some are suitable for both.
3. Climate and Seasons
Modern engine oils can cover a wide range of operating temperatures. However, certain oil grades perform better in certain situations.
Hotter climates may require the kind of oil that resists excessive thinning (like 10W-40), while colder regions might demand an oil that won’t thicken easily at lower temperatures (like 5W-30). Using the wrong oil could cause engine overheating or start-up issues.
You may also need to change your car engine oil from summer to winter.
4. Driving Habits and Conditions
Rugged driving conditions like off-roading or towing require the motor oil to work harder with a more frequent oil change service. This might call for motor oil with additives for better engine protection, in this case, to help reduce engine friction under high temperatures and heavy loads.
Short trips under 15 minutes may not allow your engine to reach maximum operating temperature consistently, meaning water condensation won’t evaporate, resulting in sludge build-up. In this case, you may need an engine oil with additives that prevent sludge formation.
5. Engine Age
Newer cars with multi-valve, high-rev engines typically demand a thinner oil to prevent start-up damage. In contrast, an older engine in a classic ride likely wants a thicker oil for correct oil pressure between worn engine parts.
We’ve gotten down to the basics of how to figure out what oil your car takes.
Now, let’s answer some FAQs.
5 Engine Oil FAQs
Here are some questions regarding car engine oil use and their answers:
1. What Do Motor Oil Viscosity Ratings Mean?
The SAE (Society of Automotive Engineers) viscosity rating, or viscosity grade, represents motor oil’s fluidity and performance at high and low temperatures. The typical format will be something like 5W-30.
The first number preceding the W (for Winter) represents the oil’s thickness at 0oF (-17.8oC). Lower numbers mean the oil runs freer in cold weather. For example, 0W-20 can flow better at low temperatures than 10W-30.
The second number represents the oil’s characteristics at running temperatures and is usually rated around 212oF (100oC). The higher this second number, the more resistant the car oil is to thinning. For example, 10W-40 is thicker at higher temperatures than 10W-30.
Viscosity ratings apply across all types of motor oil, whether synthetic or traditional. The most common oil in modern cars is the 5W-30 or 10W-30.
2. What Do Motor Oil Labels Mean?
Reputable engine oils usually have the API (American Petroleum Institute) donut and the API starburst symbol on their bottles.
The API donut should display:
- The SAE viscosity rating (this will be the usual 5W-30, 0W-20, etc.)
- A service designation on the container (showing letters like SN, SP, CK-4)
- Indication if the oil has passed the Resource Conserving test
API’s latest service standards are “SP” for gasoline (petrol) engines and “CK-4” for the diesel engine. An older engine might be perfectly content with motor oil with an API service rating of “SG,” but newer cars may need “SP.”
The API starburst symbol indicates that the engine oil has passed the service tests in the API donut. An oil stating that it “meets” an API service standard isn’t the same as one registered and tested to ensure compliance.
3. How Often Should I Change My Oil?
Oil changes are routine maintenance for your engine protection. Motor oil not only lubricates but also helps keep your engine clean by capturing contaminants and reducing sludge. Your best guide for change intervals is your owner’s manual.
Oil type does factor in, as conventional oils will degrade faster than full-synthetic or synthetic blend oils. As a general rule, you should consider an oil change for:
- Conventional oils: every 4,000 miles
- Synthetic oils: every 7,500-10,000 miles
In addition, always check your oil level before driving a long distance. The easiest way is to look at the engine’s dipstick and get a top-up or oil change if necessary.
4. Can I Mix Different Motor Oil Types?
Yes, you can, but it’s not advisable.
All API oil types are required to be compatible. Adding a regular oil (conventional oil) to a synthetic oil won’t harm either.
However, mixing will reduce the benefits of additives in the synthetic oil. It’s best to avoid mixing the types of oils to maintain the maximum benefits of the better oil formulation.
5. What Should I Do if I Have to Mix Different Motor Oils?
There may be times when you simply can’t find the exact engine oil you need.
Here’s what you can do:
- First, choose an oil from the same manufacturer as your current car’s oil. If not possible, then pick one with the same API Donut certification.
- Secondly, select a product with similar chemical and performance characteristics to what’s in your vehicle’s engine.
The Right Motor Oil Matters for Peak Engine Performance
Choosing the right oil for your car can be confusing, and using the wrong oil could end in costly engine repairs. When in doubt, always consult the manufacturer’s manual and keep up with regular oil changes.
If there isn’t a manual, there are other ways to get answers, including asking a mechanic for help.
For that, you have AutoNation Mobile Service.
We’re a mobile auto maintenance and repair solution available 7 days a week. We can do maintenance and fixes right in your driveway, and a 12-month | 12,000-mile warranty covers all repairs.
Contact us for your oil change service; our expert mechanics will drop by to lend a hand.