Choosing the right engine oil involves understanding various specifications, including viscosity ratings, industry standards, and manufacturer recommendations.
This guide provides an in-depth explanation of engine oil specification charts, their importance, and how to interpret them to ensure optimal engine performance.
Engine Oil Specification Chart
| Viscosity Grade | API Rating | ACEA Rating | ILSAC Rating | OEM Approvals |
|---|---|---|---|---|
| 0W-20 | API SP | ACEA C5 | ILSAC GF-6A | Honda, Toyota, GM dexos1 |
| 5W-30 | API SP | ACEA A5/B5 | ILSAC GF-6A | Ford WSS-M2C913-C, VW 504.00/507.00 |
| 10W-30 | API SN Plus | ACEA A3/B4 | ILSAC GF-5 | Chrysler MS-6395, GM 6094M |
| 10W-40 | API SN | ACEA A3/B4 | Not Required | BMW Longlife-01, MB 229.5 |
| 15W-40 | API CK-4 | ACEA E7 | Not Required | Caterpillar ECF-2, Volvo VDS-4 |
| 20W-50 | API SN | ACEA A3/B4 | Not Required | Older high-performance engines, motorcycles |
Why Engine Oil Specifications Matter
Using the wrong engine oil can lead to poor fuel efficiency, increased engine wear, and even severe damage. An oil specification chart helps prevent these issues by ensuring that only the appropriate oil types are used. The specifications take into account factors such as:
- Viscosity requirements (based on climate and engine type)
- Additive packages (detergents, dispersants, and anti-wear agents)
- Industry standards (API, ACEA, ILSAC)
- OEM (Original Equipment Manufacturer) approvals
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Key Components of an Engine Oil Specification
1. Viscosity Ratings (SAE Grades)
Viscosity refers to an oil’s resistance to flow and is categorized using the SAE (Society of Automotive Engineers) grading system. The most common viscosity grades found in an oil specification chart include:
- Single-Grade Oils (e.g., SAE 30) – Used in specific applications where temperature variations are minimal.
- Multi-Grade Oils (e.g., 5W-30, 10W-40) – Designed to perform well in both cold and hot temperatures.
In multi-grade oils, the first number (e.g., 5W) represents the oil’s flow in cold conditions (W stands for winter), while the second number (e.g., 30) indicates its viscosity at operating temperatures.
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2. API (American Petroleum Institute) Classification
The API classification ensures that engine oil meets minimum performance and protection standards. The two main categories include:
- API S-Series (Spark-Ignited Engines) – For gasoline engines (e.g., API SN, API SP)
- API C-Series (Compression-Ignited Engines) – For diesel engines (e.g., API CK-4, API FA-4)
Modern vehicles often require API SP-rated oils due to their improved fuel economy and emission control properties.
3. ACEA (Association des Constructeurs Européens d’Automobiles) Ratings
ACEA ratings are primarily used in Europe and provide stricter performance criteria than API. They are divided into three categories:
- ACEA A/B – For gasoline and light-duty diesel engines (e.g., ACEA A3/B4)
- ACEA C – Low-SAPS (Sulfated Ash, Phosphorus, and Sulfur) oils for modern engines with after-treatment systems (e.g., ACEA C3)
- ACEA E – Heavy-duty diesel engine oils (e.g., ACEA E9)
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4. ILSAC (International Lubricant Standardization and Approval Committee) Ratings
ILSAC certification is often used in North America and is closely related to API classifications. Common ILSAC ratings include:
- ILSAC GF-6A – Designed for improved fuel efficiency and engine cleanliness.
- ILSAC GF-6B – A newer standard specifically for lower-viscosity oils (e.g., 0W-16).
5. OEM Approvals and Manufacturer-Specific Standards
Many vehicle manufacturers have their own engine oil specifications, which are often more stringent than industry-wide standards. Some notable OEM approvals include:
- General Motors (GM dexos1, dexos2)
- Volkswagen (VW 502.00, VW 507.00)
- BMW (Longlife-01, Longlife-04)
- Mercedes-Benz (MB 229.51, MB 229.71)
Always check the owner’s manual to see if a particular OEM specification is required for your vehicle.
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How to Read an Engine Oil Specification Chart
A typical engine oil specification chart contains various columns detailing different attributes of the recommended oils. Here’s an example of what a chart might look like:
| Viscosity Grade | API Rating | ACEA Rating | ILSAC Rating | OEM Approvals |
|---|---|---|---|---|
| 0W-20 | API SP | ACEA C5 | ILSAC GF-6A | Honda, Toyota, GM dexos1 |
| 5W-30 | API SP | ACEA A5/B5 | ILSAC GF-6A | Ford WSS-M2C913-C, VW 504.00/507.00 |
| 10W-40 | API SN | ACEA A3/B4 | Not Required | BMW Longlife-01, MB 229.5 |
| 15W-40 | API CK-4 | ACEA E7 | Not Required | Caterpillar ECF-2, Volvo VDS-4 |
Choosing the Right Engine Oil Based on the Chart
To select the best engine oil for your vehicle, follow these steps:
- Check Your Owner’s Manual – The manual will specify the recommended viscosity and any required OEM approvals.
- Consider Your Driving Conditions – If you drive in extreme temperatures, opt for an oil with better cold or high-heat performance.
- Look at Industry Standards – Ensure that the oil meets the latest API, ACEA, or ILSAC standards for your engine type.
- Verify OEM Approvals – If your vehicle manufacturer requires a specific certification, ensure the oil has it.
- Choose Quality Brands – Stick to reputable oil brands such as Mobil 1, Castrol, Shell, and Valvoline to guarantee high-quality lubrication.
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The Impact of Using the Wrong Engine Oil
Using an incorrect oil specification can lead to several issues, including:
- Increased engine wear – A mismatch in viscosity can lead to improper lubrication.
- Reduced fuel efficiency – Thicker oils create more resistance, reducing MPG.
- Sludge buildup – Incompatible additives can cause deposits in the engine.
- Emission system damage – High-SAPS oils can clog catalytic converters and DPFs.
- Voided warranty – Some manufacturers require specific oil specifications for warranty coverage.
FAQs
What is the recommended engine oil specification?
The recommended engine oil specification depends on the vehicle manufacturer’s requirements, which are listed in the owner’s manual. The specification includes:
- Viscosity grade (e.g., 5W-30, 10W-40)
- API classification (e.g., API SP, SN Plus)
- ACEA ratings (e.g., ACEA C3, A5/B5)
- ILSAC certification (e.g., GF-6A, GF-6B)
- OEM approvals (e.g., GM dexos1, VW 504.00/507.00, BMW Longlife-04)
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Which oil is thicker, 5W-30 or 10W-30?
10W-30 is thicker than 5W-30 in cold temperatures because the first number represents cold viscosity. At operating temperature, both oils have the same thickness (30-weight). However, 5W-30 flows better in cold conditions, making it ideal for colder climates.
Which oil is thicker, 10W-30 or 15W-40?
15W-40 is thicker than 10W-30 at all temperatures.
- 15W means it has higher viscosity in cold temperatures compared to 10W.
- 40-weight means it is thicker at high temperatures than 30-weight oil.
- 15W-40 is typically used in diesel engines or heavy-duty applications, while 10W-30 is more common for gasoline engines.
What do the letters mean on engine oil?
The letters in engine oil viscosity grades (e.g., 5W-30) stand for:
- W = Winter (indicates oil’s performance in cold temperatures).
- The first number (before “W”) = Cold temperature viscosity (lower number = better cold flow).
- The second number (after “W”) = Viscosity at high operating temperatures (higher number = thicker oil when hot).
For example, in 5W-30, the “5W” means it flows well in cold temperatures, and “30” means it maintains good thickness at high temperatures.
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What are the SAE grades of oil?
SAE (Society of Automotive Engineers) grades define engine oil viscosity. The most common SAE viscosity grades include:
- Single-grade oils: SAE 30, SAE 40, SAE 50 (mainly used in older engines and specific applications).
- Multi-grade oils: 0W-20, 5W-20, 5W-30, 10W-30, 10W-40, 15W-40 (used in modern engines for better performance in various temperatures).
Which motor oil is thicker, 5W-30 or 10W-40?
10W-40 is thicker than 5W-30 at both cold and high temperatures.
- 10W vs. 5W: 10W is thicker in cold conditions than 5W.
- 40 vs. 30: 40-weight oil is thicker at high temperatures than 30-weight oil.
10W-40 is usually used in older or high-performance engines, while 5W-30 is common in modern engines for better fuel efficiency.
What happens if I put 10W-30 instead of 5W-30?
If you use 10W-30 instead of 5W-30, it may cause:
- Slower cold starts in cold climates (10W is thicker than 5W in cold temperatures).
- Reduced fuel efficiency due to increased resistance at startup.
- Potential warranty issues if your manufacturer specifically requires 5W-30.
However, in warm climates, the difference is minimal, and your engine should run without problems.
What happens if I use 10W-30 instead of 10W-40?
If you use 10W-30 instead of 10W-40, it will result in:
- Thinner oil at high temperatures, which may reduce protection in high-heat or high-load conditions.
- Slightly better fuel efficiency since thinner oil reduces engine resistance.
- Potential issues in high-performance or older engines that require thicker oil for better lubrication.
The difference is small for most vehicles, but 10W-40 may be preferred for extra protection in high-performance or high-mileage engines.
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What happens if I use 10W-40 instead of 5W-30?
If you use 10W-40 instead of 5W-30, you may experience:
- Thicker oil at cold temperatures leads to harder cold starts and slower oil circulation.
- Reduced fuel efficiency due to increased engine resistance.
- Potential oil pressure issues in modern engines, which are designed for thinner oils like 5W-30.
If your engine requires 5W-30, it’s best to stick with it unless your owner’s manual permits 10W-40 in certain conditions (e.g., high temperatures or high-mileage engines)
Final word
Using an engine oil specification chart is essential for maintaining your vehicle’s performance, fuel economy, and longevity. By paying close attention to viscosity ratings, industry classifications, and OEM approvals, you can make an informed decision when selecting the best engine oil for your vehicle.
