Can you put 5w30 in a 5w20 engine?

The engine is the most vital component in any vehicle and the right engine oil plays a very important role in ensuring the longevity and durability of the engine. Engine oils come is various viscosities and each engine is usually built for an engine oil of specific viscosity. So, the comparison today is between two engine oils of different viscosities, namely 5w30 and 5w30. Well, these names of the oils look almost similar, so it is likely that they have similar specifications too?  Can these engine oils be used interchangeably without facing any side effects?

Sadly, the answer is a no! While both the oils have similar winter viscosities, you will see differences between the two in higher temperatures.  So, 5w30 is likely to become thicker and more resistant once the temperature reaches 104°F. This would lead to side effects such as reduced horsepower and fuel efficiency. So, no, you cannot put 5w30 engine oil in a 5w20 engine without facing any negative side effects.

Due to their common winter viscosities, there are unlikely to be any differences in the cold temperatures. So, let’s start with a table comparing both the engine oils in different parameters under warmer conditions–

Suitable EnginesEngines Operating at Relatively Higher TemperaturesEngines Operating at Relatively Lower Temperatures
Fuel EfficiencyLowHigh
Exposure to high TemperaturesVery Durable, Doesn’t Evaporate EasilyEvaporates Easily
Engine PerformancesLow Performance, High PowerHigh Performance, Low Performance


Similarities Between 5w30 vs 5w20 Motor Oil

Thickness in Cooler Temperatures

Due to its common winter viscosities, both engine oils have the same thickness at lower temperatures. It means both the oils will remain thick and flow well even if the temperature drops. So, the engine is more likely to start easily in cold temperatures, which means there are lesser chances of you being stuck with a car with failed ignition on a winter morning.

Differences between 5w30 and 5w20 engine oils are –


Suitable Engines

5w30 is multi-grade engine oil that is primarily suited for heavier engines that run in high temperatures. Similarly, 5w30 also performs better in warmer climates as the thickness of the oil ensures that it doesn’t evaporate in higher temperatures, unlike 5w20 which can easily evaporate if the temperatures rise. So, if 5w30 is put in a 5w20 engine, it is likely that the thicker viscosity of the engine oil will make it unsuitable for lighter engines.


While both the engine oils have lower viscosity in cold temperatures, the thickness of 5w30 increases drastically once the temperatures start to rise. In higher temperatures, the 5w30 becomes thick and resistant while the thinner 5w20 may start to evaporate. The thickness of the 5w30 oil provides added protection to the engine but the mileage reduces drastically. However, in regular temperatures, there is almost no difference in the specifications of the fuels.

Also Read:-

Can you put 10w30 in a 5w20 engine? Only Facts!

Fuel Efficiency

Due to its thickness, 5w30 is less fuel-efficient than 5w20 at higher temperatures. It is because 5w30 is more resistant and hence it requires more effort to pump the fuel. Further, the increased thickness of the 5w30 is likely to lead to more drag in the engine components such as the crankshaft. However, 5w20 is more fuel efficient due to its lower viscosity at higher temperatures.

Exposure to High Temperatures

5w30 engine oil is more suited for engines that operate at higher temperatures or in warmer climates. It is because 5w20 is likely to evaporate if the temperatures rise and the friction will begin to reduce, leading to severe wear and tear.

Engine Performance

While both the engine oils provide similar performance in regular temperatures, 5w30 engine oil fares better on days when the mercury shoots up. When there is excessive heat, your engine oil may start to evaporate, leading to reduced friction which could harm your engine in the long run. So, the 5w30 engine ensures that your engine doesn’t stall or splutter and runs smoothly on extreme summer days.

Suitable Climate

Due to the difference in viscosities, 5w30 is more suited for vehicles that function in extremely hot weather. Due to the high temperatures, 5w20 engine oil is likely to evaporate and lead to an increase in wear and tear in the engine parts. However, 5w30 starts to thicken as the temperatures rise and provide improved protection and lubrication to the engine. So, while 5w20 is ideal for colder temperatures, 5w30 provides better protection when the temperatures shoot up.


5w30 thickens at high temperatures to provide the required lubrication and protection to the engine to the extra heat. However, 5w20 is likely to evaporate and eventually lead to increased friction and wear and tear in the engine. So, if you live in a place where the mercury rises too often, you might just want to use 5w30 to prevent your engine from stalling.

Also Read:-

5w30 vs 5w40 Engine Oil | Complete Difference with Facts


Is 5w30 or 5w20 better for engine mileage?

As the name suggests, both 5w30 and 5w20 oils have a similar winter viscosity. It means that on extremely cold days or even regular days, there would be little difference in the fuel efficiency of either oil. However, the difference comes when the temperature starts to rise as the 5w30 engine oil becomes thicker. This thickness leads to the oil being resistant and hence requires more efforts to pump the fuel and also leads an increased friction between the engine parts. This invariably leads to a drop in the overall fuel efficiency of the car. So, while both the engine oils provide equal mileage in normal temperatures, the mileage of 5w30 will start to drop as the temperature rises beyond the regular levels.

Pro tip – While changing your oil time may seem an interesting thing to do, it is best to stick to the company recommended oil if your car is under warranty. The moment you chose to swap the engine oil with something beyond the manufacturer’s recommendation, your powertrain warranty is likely to become void.


Can I use 5w30 instead of 5w20 in my ford f150?

The Ford 150 is one of the most popular pick-up trucks in the United States and all Ford 150 pick-up trucks are specified to use either 5w30 or 5w20 engine oils. However, the requirement of either 5w30 or 5w20 specifically differs for each production year and model of the truck. So, it is best to adhere to the oil recommendation stated by the company in the owner’s user manual. However, if you have a gallon of 5w30 oil left behind and your Ford 150 uses 5w20, that doesn’t mean that you have to throw it all away. You can easily use 5w30 oil in place of 5w20 without any instant problems in the performance. Although prolonged usage of 5w30 oil in an engine specified for 5w20 will definitely lead to problems for your Ford 150.

Is 5w20 or 5w30 more suited for summers?

5w30 is definitely better suited for extremely hot summers. However, the difference can only be felt if you have the temperatures touching the extremes. So, if you have one extremely hot summer in a place that generally has normal summers, shifting from 5w20 to 5w30 doesn’t make sense. So, 5w30 is better suited for places that have extreme climates like deserts, but 5w20 makes a decent option for places with moderate summers.

Can I use 5w20 in place of 5w30 in a Subaru?

No, swapping 5w20 in place of 5w30 would not be a good idea. The 5w20 is a thinner oil that is better suited for newer engines, unlike in a Subaru, which uses old engines. The added thickness of the 5w30 helps provide extra protection to the Subaru engine. So, the thinner 5w20 oil is likely to evaporate and cause increased wear and tear to the Subaru engine which operates at higher temperatures in the long run. However, you can still use the 5w20 instead of the 5w30 for a few weeks if necessary and if the weather isn’t too hot, without facing any severe issues with your Subaru.

What can I use instead of 5w20?

While it is best to stick to the company specified engine oil for your vehicle, in this case 5w20, you can still choose to use other engine oils of similar viscosity for shorter periods such as a few weeks without harming the vehicle’s engine. However, it will still have effects such as reduced mileage and horsepower output since it is a engine specifically designed for the 5w20 engine oil. However, supplementing 5w20 with an engine oil of different viscosity may lead to severe problems in the long run and is not recommended.


Is 5w20 good for mileage?

Yes, 5w20 is a thin oil that is good for mileage. Its low viscosity causes less friction and drag in engine parts such as the crankshaft and the piston. Further, its thin nature allows it to flow more freely and enables it to use less effort to pump the fuel. The reduced friction and efforts eventually save up more energy which translates to better mileage for cars. Thus, 5w20 indeed provides great mileage.

Is 5w30 good for mileage?

In lower temperatures, 5w30 stays thin owing to the lower temperatures. This helps ensure better mileage in your car. However, as soon as the temperatures rise, the oil starts to thicken and becomes resistant to flow. This leads to extra protection for the engine part but it also means a fall in the friction levels. This eventually causes a drop in the mileage of the vehicles. So, while 5w30 provides good mileage in colder or operational temperatures, it affects the mileage of the vehicle negatively as soon as the temperatures rise.

Can you mix 5w20 and 5w30?

Yes, you can definitely mix both the 5w20 and 5w30 oils together without the sky starting to fall off. Both the oils would not blend but stay separate. However, there may be some slight variation in the overall performance depending on the mixing ratio of both the oils. While it is safe to mix both the oils, it is best to mix oils of the same brand to ensure that there aren’t too many differences between the oils.


While you can indeed put 5w30 in a 5w20 engine for shorter periods, it is important to understand that the 5w20 engine has been specifically designed for the 5w20 engine oil. Since the winter viscosities of both the oils are similar, they are likely to provide the same performance in the colder temperatures. However, if you continue to use 5w30 oil in the 5w20 engine for prolonged periods, chances are that your engine might be damaged negatively. So, unless you live in a desert like region with extremely high temperatures and have a car with a 5w20 engine, it is definitely not recommended to use a 5w30 oil in a 5w20 engine.