Can I use 5W-30 instead of 10w 30 oil?

Yes, in many cases you can, provided your vehicle’s manufacturer approves it. The practical difference is mostly how the oil behaves when the engine is cold; at operating temperature, 5W-30 and 10W-30 are typically similar. Always check your owner's manual or the oil specification label to be sure.

Understanding oil viscosity ratings

Oil viscosity ratings tell you how thick or thin an oil is at different temperatures. The first number followed by a W (for winter) indicates cold-flow behavior—the lower the number, the easier the oil flows when starting in cold weather. The second number (the “30” in 5W-30 and 10W-30) represents viscosity at engine operating temperature. Multi‑grade oils like 5W-30 and 10W-30 are designed to perform well across a range of temperatures, but the exact suitability depends on the engine and climate.

What the numbers mean in practice

5W-30 is generally thinner than 10W-30 at cold startup, which can reduce startup wear and improve starting reliability in cold weather. At operating temperature, both oils typically share similar viscosity characteristics, and either can meet the same performance standards if the oil specification (API/ILSAC/ACEA) and the engine’s requirements are satisfied.

Can I switch from 10W-30 to 5W-30?

Before making a switch, there are several factors to consider. The following list summarizes the most important considerations to determine whether a change is appropriate for your car.

Key considerations before substituting viscosity

• Manufacturer approval: Check the owner's manual or the oil specification label to see the approved viscosity range for your engine. If the manual lists both 5W-30 and 10W-30 (or a range that includes them), switching is typically acceptable.


• Climate and temperature range: 5W-30 is advantageous in cold climates due to easier cold starts. In very hot climates, 10W-30 may be preferred if specified or if the engine experiences higher oil temperatures.


• Engine condition and age: Newer engines with tight tolerances often tolerate 5W-30 well, while older or high-mileage engines that consume oil or operate under heavy load might benefit from the thicker end of the range or a specialty oil.


• Warranty and service requirements: Some warranties specify a particular viscosity or brand; deviating from the recommended specification could affect warranty coverage.


• Oil type and specification compatibility: Ensure the oil meets the correct API/ILSAC/ACEA specifications and, if applicable, the OEM’s dexos or other requirements. Do not mix different viscosity grades unless you’re able to drain and replace with the correct grade promptly.

If you choose to switch, do so only within the approved range and use an oil that meets the exact specifications called for by the manufacturer. Mixing oils or using an unapproved viscosity can lead to reduced lubrication performance, increased engine wear, or warranty concerns.

What to do if you’ve already used 5W-30

If you’ve already filled with 5W-30 in a vehicle that requires 10W-30, monitor oil levels and engine performance. If the manual allows 5W-30, you’re likely fine to continue with the next oil change using the correct grade. If the manual requires 10W-30 specifically, plan to revert at the next oil change and consult a mechanic if you notice unusual symptoms such as increased oil consumption, noise, or leaks.

Practical steps for a smooth transition

• Verify the correct viscosity range in the owner's manual or service documentation.


• Choose an oil that meets the exact API/ILSAC/ACEA specifications and OEM requirements.


• Ensure the oil’s grade is consistent with the recommended change intervals and drought conditions you face.


• Stick to the recommended oil change intervals and monitor oil level and consumption after the switch.

In short, switching from 10W-30 to 5W-30 is often acceptable when the manufacturer approves it, especially for cold-weather operation. In climates with extreme heat or in certain engines, sticking with the higher end of the range or the exact grade specified remains the safest course.

Practical guidance for hot and cold climates

Engine oil is a critical part of vehicle reliability across climates. For extreme cold, 5W-30 helps with cold starts; for very hot environments or engines with heat-related stress, staying with 10W-30 or a specification that tolerates higher temperatures may be preferable if required by the manufacturer.

Always prioritize the official specification for your vehicle. If in doubt, consult your dealer or a trusted mechanic who can confirm the correct viscosity for your engine under your typical operating conditions.

Summary

Most modern engines can tolerate a switch between 5W-30 and 10W-30 when the change stays within the manufacturer’s approved viscosity range and specifications. The key is to check the owner's manual, consider climate and engine condition, and adhere to OEM requirements and service intervals. When in doubt, seek professional advice to avoid potential warranty or lubrication issues.

Is there a big difference between 5W and 10W?

In other words, a lubricant with SAE 5W-30 will behave better when cold than a lubricant with SAE 10W-40. In contrast, oils with a higher SAE after the W generate thicker films of lubricant and better protect the mechanical parts when the vehicle is already hot.

Is it better to use 5w30 or 10W30 in the summer?

5W30 acts like a 5 weight oil when cold and 30 weight when hot. 10W30 acts like a 10 weight oil when cold and 30 weight when hot. They'll behave the same when used in a lawn mower in summer. If you're mowing lawns when it's -20F the 5W30 will be slightly easier to start.

What other oil can I use instead of 10W30?

AMSOIL 0W-30, 5W-30 and 10W-30 synthetic motor oils are ALL 30 weight oils. The answer is that ANY one can be used regardless of the vehicle owners manual recommendation. To better understand, in a 5W-30 oil, the "W" stands for winter performance.

What happens if I put 5w30 instead of 10W30?

Yes, you can use 5W-30 instead of 10W-30 because they have the same viscosity at operating temperature (SAE 30), but 5W-30 flows more easily when cold, which is better for cold starts and in colder climates. While it is generally safe to use 5W-30 where 10W-30 is recommended, it's always best to check your vehicle's owner's manual for the specific manufacturer's recommendation. 
When to use 5W-30 instead of 10W-30

• For cold weather: 5W-30 is ideal for climates that experience cold temperatures because the "5W" indicates it flows more easily when cold, which can reduce engine wear during startups. 
• For a wide temperature range: 5W-30 is a versatile choice for all-season use since it handles both cold and operating temperatures well. 
• To reduce startup wear: The thinner 5W-30 will circulate faster upon startup, providing quicker lubrication to vital engine parts. 

Key differences

• Cold viscosity: The first number (555 vs. 101010) indicates the oil's viscosity in cold temperatures. A lower number means the oil is thinner and flows better when cold. 
• Hot viscosity: The second number (303030) indicates the oil's viscosity at normal engine operating temperature (212∘F212 raised to the composed with power cap F212∘𝐹 or 100∘C100 raised to the composed with power cap C100∘𝐶). Both 5W-30 and 10W-30 are the same thickness once the engine is hot. 

This video explains the difference between 5W-30 and 10W-30 motor oils: 53sThe Savvy ProfessorYouTube · Apr 19, 2023
Important considerations

• Always check the owner's manual: The manufacturer's recommendation is the most important guide for which oil to use. 
• Don't switch from 5W-30 to 10W-30 unless recommended: Switching to a thicker oil (101010W) where a thinner one (555W) is specified can cause extra wear, especially in very cold climates. 

You can watch this video to learn what happens when you use 10W30 instead of 5W30: 1mAuto V Fix YouTube · May 24, 2023