You might be aware of the engine oil expansion when it’s hot but does oil get thinner when hot? Absolutely yes. But you should keep several key factors in mind while dealing with the topic.
With an increase in the temperature, there is a certain decrease in the viscosity of any liquid, making it easy to pour and flow. But that might not be the best thing for your engine in all terms. Please read this blog to know how it affects your vehicle.
Does Oil get Thinner When hot and Why?
When a vehicle is on the road for long durations, the internal combustion in the engine produces a lot of heat energy which raises the engine oil’s normal temperature and nearby surfaces.
High temperatures can change the motor oil on the molecular level. Higher than-expected temperatures can break down the oil molecules into smaller molecules which affect the oil’s viscosity. This change in viscosity makes the oil thinner.
How to prevent Oil from Thinning?
If you feel the motor oil you use keeps wearing out and gets thinner now and then, you should think of switching to synthetic oil. Mineral oils tend to lose viscosity when operating at higher temperatures.
Synthetic oils have special additives that give them special qualities to withstand high temperatures in the engine and reduce the chances of oil getting thinner when hot.
Why Thickness of the Oil Matter?
Thin oils are less viscous in nature and can be poured easily, even at lower temperatures. Engines mostly used in colder climates are designed to perform best when thinner oils are used, as they reduce friction and aid the engine in starting quickly. Also, such oils don’t freeze in cold temperatures.
On the contrary, thick or more viscous oil is used in engines that require keeping a layer of oil between the metallic surfaces at all times, maintaining protection for the parts. Thick oils are mostly used in hotter climates.
Is it okay to use thin oil?
Again, what is thin and what is not depends on your vehicle. Any engine’s requirement depends on what fuel it consumes, the climate in the region the vehicle is used, how heavy the load is, and several other factors.
We recommend checking the owner’s manual to find the best oil to use.
Why is my Engine oil getting thinner even when not hot?
Suppose you are unsure why your engine oil keeps getting thinner even after refilling it from time to time. Your machine might be facing one of the two problems.
Your oil can get thin if liquid other than motor oil leaks into the oil pan. These liquids can be any solvent used in your engine or main fuel.
Another, and the most common, the reason is using expired oil (oil doesn’t easily expire). This oil might have lost its VI (viscosity index) improviser. These are additions in oil that help them maintain their viscosity in high temperatures and for a longer period.
How to Know Engine Oil Thickness?
The engine oil you use comes in a tin/box/container. You need to look for a number in the format “XW-XX”.
The numbers after the dash represent the viscosity rating at 100 degreesCelsius. A higher number tells that the oil is thicker, and a lower number shows that the oil is thinner.
The W to the left of the dash represents Winter, and the number along with the W represents the flow of oil at 0 degrees Celsius.
For example, a 5W-30 motor oil will have a better flow than a 10W-30 at 0 degrees, and the same oil will have a better flow than a 10W-40 at operating temperatures.
Marc is a Young mechanic working full-time in a big garage in Texas. He’s graduated and is well educated in the automobile industry and aims to open his own shop someday for his clients.