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Will higher viscosity oil reduce oil consumption?

Announcement posted by Affordable Training 02 Jul 2022

People often ponder if it is okay to use oil that is thicker or thinner than what the maker of their engine suggests. Whether it's okay to substitute 10W-30 oil for 5W-30 oil, for instance, is a frequently asked issue. While following the instructions in your owner's handbook is ideal, there is often no long-term damage if you accidentally use a viscosity that is one grade higher or lower.

What Enhances the Consumption of Oil?

Oil usage is one of the most feared issues that automobile owners confront. Some individuals only have to deal with motor oil-related issues when they discover that the level is too low and has to be topped up. That's presuming that the repair business, and not the owner, does the routine oil change. If you didn't observe the increased oil use until the last oil change, it's simple to assume that the oil is to blame. The reality, however, is more complicated.

There are several reasons for using oil. Let's simply go over the most typical ones:

  • Engine layout - Some engines deliberately use oil. The rate of consumption might reach 1 liter per 1000 kilometers. If oil consumption is important to you, you are better off asking questions about it in forums because it depends on the brand and model of the engine.
  • Driving style - Oil use is influenced by RPM. More oil will be utilized the higher your typical RPM is. This is due to increased pressure on the gaskets and seals, which causes some oil to move about and burn off in the combustion chamber.
  • Condition of gaskets and seals - More oil will be used as they get more worn. The identical thing that I explained in the last section occurs: the oil manages to get past the seals and either leaks out or is burnt off in the combustion chamber.
  • Inadequately viscous motor oil - You will suffer oil consumption for the same reason as explained in the previous section if you use an oil with a viscosity that is lower than that advised by the engine manufacturer. I don't just mean SAE viscosity when I say "viscosity." Additionally taken into account is the HTHS viscosity. For instance, you could need more oil when using an ACEA A1/B1 oil with a lower HTHS viscosity than when using an ACEA A3/B3 oil with a higher HTHS viscosity.
  • High volatility motor oil of low grade - This is the final reason I'll discuss since it's the least prevalent. The rate of oil consumption may show signs of very high oil volatility.

There are various more causes as well, such as excessive oil levels, damaged or clogged engine components, and oil contaminated with gasoline.

A Specific Motor Oil Viscosity Must Be Used in Engines

More precise tolerances are used in the construction of modern sophisticated engines than in earlier models. One difference is the narrower spacing between the main bearings and the crankshaft journals. This is done on purpose to enable the use of motor oils with lower viscosities, such as 0W-20 and even 0W-16, in current engines.

Since they flow more readily than higher-viscosity lubricants, lower-viscosity oils minimize internal friction and increase fuel efficiency. Automakers are turning to low-viscosity lubricants to help them fulfill the criteria as fuel-economy demands become increasingly stringent.

Oil that is thicker could not flow as quickly.

Brad's 15W-50 racing oil may not be able to flow rapidly enough when the engine is running to cover the voids between the crank journals and main bearings because it is too thick.

Metal-to-metal contact and wear will be permitted since the oil won't consistently produce a lubricating coating. His engine's specifications require for the usage of 0W-20 oil, which has a lower viscosity. Due to its decreased viscosity, it flows more quickly and can cover even the smallest gaps between components, forming a steady, long-lasting lubricating coating.

Additionally, the engine will use energy pumping the heavier oil, decreasing fuel efficiency. Sinopec noted that the operating temperatures will rise as a result of thicker oil's reduced ability to transmit heat, which might speed up chemical breakdown (also known as "oxidation") and produce toxic sludge and deposits.

His earlier engine wasn't constructed with Brad's engine's exacting standards. Additionally, once the engine reaches working temperature, both oils have the same viscosity. He is aware of this due to the similarity of the second digit, or "30," in each oil's viscosity rating. It represents the oil's flow resistance at typical operating temperature, or 212°F (100°C). However, using 10W-30 as opposed to 5W-30 could make cold starts more challenging.

Consider the "W" as standing for "winter" to make sense of it. The oil will flow more easily when it is cold the lower its "W" viscosity. In this scenario, 5W-30 will start to flow more readily than 10W-30. In fact, depending on the conditions, several manufacturers let you swap to a lower viscosity oil.

Thickness May Not Be In

Imagine John deviating from the prescribed viscosity and using 0W-16 in his 1998 Corolla instead. Using a thinner oil may have the same effect on Brad's engine as using one with a viscosity that is too high. Too little oil may make it difficult for a constant lubricating coating to form, which invites wear-causing metal-to-metal contact.

The difficulty is increased by extreme stress and heat. Oil thins when heated, therefore when heated to an excessive temperature, already thin oil gets considerably thinner, compounding the issue. If your car has a variable valve timing system, too little oil pressure might potentially prevent it from functioning correctly. Low pressure may also cause lifters to lose contact with the cams, which would increase wear and make noise.

Final words

It probably won't cause long-term damage to use a viscosity one grade higher or lower than what is advised for your engine. But it's better to use the viscosity suggested in your owner's handbook to allay any worries concerning engine protection and your car's warranty.

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