Can I use 10W40 instead of 20w40? here’s why


You may have noticed that your car’s oil is a bit low after you took it for a drive. It’s time to change the engine oil, but which one should you use? The answer depends on what type of engine your vehicle has. If you have a car with a gasoline engine, use SAE 20W-40. For diesel engines, use SAE 15W-40 or SAE 0W-30. If your vehicle has an automatic transmission, you should also use the appropriate type of oil for that.

Replacing a 10W-40 with 20 W oil will allow you to travel in colder weather without having your car sputter, stall or overheat. It also prolongs the life of many parts, including clutch plates and brakes, making this simple fix worth doing if it’s time to update fluid levels.

The 40 in 10w-40 means that the oil must fall within certain viscosity limits at 100°C. This is a fixed limit, and all oils with an ending number like 40 will achieve these specifications when heated to boiling point (pasteurization). 

Once again, lower numbers mean more thinning: 30-grade motor oils are less thick than their counterparts rated at 45 or above.

The 20W-40 is an example of winter-grade motor oil. It has been shown to perform better in low temperatures, crucial for starting your car during cold weather conditions. Living far from sea level where heating costs may not always reach max output levels due to congestion, etcetera.

Also Read: Can I use 10W40 instead of 20w40? here’s why

Can I use 10W-40 instead of 20w50??

Suppose you’re using a 20W-50 motor oil instead of 10w 40. In that case, it’s important to keep in mind that the increased viscosity will cause more resistance against the flow, leading to greater engine operating temperatures and an increase in fuel consumption. 

The best way around this problem is to simply drain all old fluids and install new ones with appropriate grades for your vehicle requirements.

20W-50 is not the best oil for your car in cold weather. Consider draining and refilling if you live somewhere with colder temperatures, like Alaska or Canada.

Putting 20W-50 in your engine designed for 5 W -30 will not kill it right off. What might happen is that the thicker oil would be difficult to pump when cold, and you could experience excessive wear on the startup.

A more accurate way of putting this: Putting too much weight onto a small surface causes friction, increasing heat from both ends.

The colder it gets, the more wear and tear your engine will experience. At higher temperatures, oil can become thick enough to prevent proper lubrication between high tolerance parts which could lead to excessive machine use over time due to reduced efficiency because there isn’t any clearance for dirt or other particles inside the system during operation.

Depending on the type of engine your car has, you may be able to use SAE (Society of Automotive Engineers) grading. For instance, if you have a diesel vehicle with an automatic transmission that uses 20W-50 grade oil, then it is possible for a non-diesel vehicle using the same specification of SAE 20W-50 grade motor oil would be compatible. 

This works as long as both vehicles are running and/or manufactured in roughly the same year range since changes have been made over time to each model’s engineering specifications that could change or render previous assumptions incompatible.

For example, if your 2003 Ford Taurus was built from early 2000 until mid-2007, your friend owns a 2007 Ford Taurus built from mid-2007 to late 2009 model year. You would need to use the newer “Fully Synthetic” motor oil for your vehicle since it was a later model and had different specifications than its 2003 counterpart or risk harming the engine.

It should also be noted that there are other types of oils available such as High Performance (20W50), Semi-Synthetic (30w40), etc. Depending on the application, these can all work but only if they meet both manufacturer’s original specification AND current API / SAE standards regardless of whether they were intended for gas OR diesel engines.

Can I use 10W40 on my motorcycle?

Motorcycles that require a 10W40 engine oil should not use 5W because the thinness of this type will cause problems when starting up. The best option for these types would be an appropriately sized automotive or industrial grade filter designed with higher flow rates in mind.

Motorcycle oils are usually of a lighter grade, such as SAE 20W-50. The “20” denotes the viscosity at low temperature in centistokes (CST), while the “50” refers to its high-temperature viscosity rating in CST. 

This is because motorcycles engines and transmissions experience wide variations in temperatures due to their operating conditions. Motorcycle oil must be less viscous when cold than auto oil for easier starting and more viscous when hot for better protection from wear tear under extreme heat. 

Otherwise, it would not lubricate effectively overall engine speeds/load ranges or during engine acceleration or deceleration cycles like upshifting and downshifting, respectively, creating very high and very low temperatures.

Can I use SAE 20W-50 in my car?

SAE (Society of Automotive Engineers) grading denotes the viscosity grade range and its corresponding temperature capability, based on how easy it will flow at any given temperature. 

A lower number means that motor oil flows more freely. For instance, an SAE 0w-20 will have a higher pour point than an SAE 50w90 because it can withstand colder conditions with fewer molecules of liquid present within the engine’s hot internals before solidifying into varnish while still maintaining enough thickness to lubricate effectively within normal operating conditions. 

An 80 weight oil (such as Castrol GTX High Mileage Full Synthetic) will have a higher viscosity index than, say, vegetable oil or SAE 50w-90. The chart below is an example of how to interpret the numbers:

The “W” in the SAE grade number stands for winter and refers to the minimum temperature at which that specific grade should be used. A lower number means it can withstand colder conditions with fewer molecules of liquid present within the engine’s hot internals before solidifying into varnish while still maintaining enough thickness to lubricate effectively within normal operating conditions.

Can I use 10w30 instead of 20w40?

The 10w30 will float over 20w40 at high temperatures, so it’s a good choice for normal working conditions. But during winter sessions, you might want to consider using something different like 5W-20 or 15 weights of synthetic oils instead because they’re less susceptible to cold temperatures, which can cause the engine to seize if not warmed up enough before being put into use again in these months.

The 20w40 engine oil will be just as good for your car, but it’s also better at protecting and enhancing the life of its parts. Larger automakers recommend changing out 10-weight motors with lighter weights like this extravaganza every 3 months or so, while smaller ones find themselves needing more time between changes (around 6 weeks).

Yes, you can still use the lower viscosity for your vehicle’s engine. It all depends on how cold it will get in where you live. Suppose there is a temperature change between day and night or season to season changes that might cause wide variations. 

In that case, this may be more applicable for those living outside Canada/US borders with different climates. If anyone has any experience with doing so, please comment below. I’ll include some links at the bottom that go into additional detail about choosing motor oil based on whether one lives far north (cold weather) or south (hotter climate).

Don’t buy a used vehicle without a VINReport.Opens in a new tab.CARFAX and Autocheck are too expensive.

Is 10W40 good for petrol engines?

Yes, any grade of oil that meets both the engine manufacturer’s original specification and current API / SAE standards will be good for a petrol engine. The main difference between oils is the viscosity rating, which refers to how easily the oil flows at different temperatures. 

A lower number means it can withstand colder conditions with fewer molecules of liquid present within the engine’s hot internals before solidifying into varnish while still maintaining enough thickness to lubricate effectively within normal operating conditions. 

So if you’re living in an area with extreme temperature changes (i.e., winter and summer), using a lower viscosity motor oil such as SAE 20W-50 would be ideal. Otherwise, stick with what the vehicle manufacturer recommends would be a safe bet.

Jim Harmer

I am Jim Harmer and I am in love with the outdoors. I share all the information I know on all activities I like doing in my home in this website. You are welcome to read and reach out for more information.

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