Does engine oil lose viscosity over time?



Oil degrades over time. The longer it sits, the less viscous it becomes and thus, the less effective it will be at keeping various engine components properly lubricated.

Does oil viscosity degrade over time?

Over time, it becomes less viscous thus less efficient in maintaining proper lubrication between moving components. Your motor oil might eventually break down depending on the oil type and the additives contained in the lubricant.

Does engine oil get thinner over time?

Because oil gets thinner as it heats up. Or you could say it gets thicker when it cools down. Say your engine needs 30-weight oil when it is running at operating temperature.

Does synthetic oil lose viscosity over time?





Even without additives, a synthetic 5W-30 motor oil will not degrade or change viscosity—it may only become slightly thicker from contaminants.

Why does engine oil lose viscosity?

Oils operating at extreme high temperatures can begin to crack thermally. The high temperatures can sheer/crack the oil molecules into smaller molecules, which causes a decrease in viscosity.

Can I use 10 year old engine oil?

Old, expired oil may not be as efficient as fresh oil, and it may damage your engine parts. Plus, it can lead to problems like acid buildup, inevitably resulting in corrosion. It is best to dispose of any expired oil to prevent further damage to your engine parts and the car’s engine fuel performance.

What happens to engine oil as it gets older?

Over time, your engine oil begins to break down and wear out. This causes the oil to become increasingly less effective at lubricating your engine’s parts and absorbing heat.

Is it better to use thicker oil in older engines?





A: Yes. This is a practical method to improve oil pressure in an older, high-mileage engine. The slightly thicker oil film from the heavier base weight oil — 10W — can help protect worn engine bearings as well.

Does used oil get thinner?

While many people assume that oil gets thinner after extended periods, the opposite is true! Engine oil actually becomes thicker over time as a result of oxidation. Depending on such factors as the temperature, moisture, oxygen levels, engine condition, and catalytic reactions, the oil will oxidize at a specific rate.

What happens if I use 10W40 instead of 5W-30?

As 5W30 is a thin oil, mixing it with 10W40 will give you a much thinner oil. Eventually, it will increase its operational capability in cold weather. But, it will not be good enough in hot weather.

Why can’t you go back to regular oil after synthetic?

Myth: Once you switch to synthetic oil, you can never switch back. This is one of the most persistent myths about synthetic oil—and completely untrue. You can switch back and forth at any time. In fact, synthetic blends are simply a mixture of synthetic and conventional oils.

Can I change oil every 2 years?

Simply put, as a general rule, manufacturers recommend that you change the oil for a gasoline engine every 10,000 to 15,000 km, or about once a year for “regular” usage (frequent but not intensive) or once every 2 years if used less frequently.



When should you not use synthetic oil?

Better For Older Engines



This being said, however, it is still not recommended to use synthetic oil in engines that have experienced significant actions – specifically, those that have reached around 75,000 miles on the odometer.

Do I need to change oil if car has been sitting?

The answer is, no. If your vehicle is sitting unused, dirt and dust can still dirty the engine oil. Another thing that can happen is moisture can begin to build up, especially if your car is in a damp or cold area such as a garage.

How can I tell if my oil is still good?


Quote from video: This little yellow loop is usually where the oil check is alright. And if you use a nice clean paper towel. Okay I'm gonna wipe off the oil on the end of the stick. And you can see how brown.

Is it OK to change oil once a year?

Most people should change their oil twice a year. Basically, once every six months. But if you find yourself driving a ton, or doing a lot of rough driving (high acceleration, lots of stop and go, etc.) check your owner’s manual and account for your driving style.

What factors affect oil viscosity?

The principal factors affecting viscosity are:



  • Oil composition.
  • Temperature.
  • Dissolved gas.
  • Pressure.


What causes viscosity breakdown?

Thermal breakdown occurs when a car’s internal heat causes a chemical reaction in the motor oil, which causes the oil’s viscosity to change. The high level of heat actually causes the oil to degrade, or break down.

What causes viscosity to change?

Viscosity changes based on load and temperature. When temperature increases, the lubricant becomes thinner and the viscosity becomes lower. Inversely as the temperature decreases, the lubricant thickens and viscosity increases, making it more difficult to pour or pump.

Does oil get thinner when cold?

If it flows slowly, it gets a high rating. Your engine needs oil that is thin enough for cold starts, and thick enough when the engine is hot. Since oil gets thinner when heated, and thicker when cooled, most of us use what are called multi-grade, or multi-viscosity oils.

Should you use thicker oil in an older engine?

A: Yes. This is a practical method to improve oil pressure in an older, high-mileage engine. The slightly thicker oil film from the heavier base weight oil — 10W — can help protect worn engine bearings as well.



Is Thicker oil better in winter?

Thin oils have lower viscosity and pour more easily at low temperatures than thicker oils that have a higher viscosity. Thin oils reduce friction in engines and help engines start quickly during cold weather. Thick oils are better at maintaining film strength and oil pressure at high temperatures and loads.