Why Do Cars Need Oil: Why does it need changed out?

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What’s the biggest key to extending the life of your vehicle? Optimal driving conditions help, and safe, defensive driving is important when it comes to avoiding accidents. Extended warranties can help add years to your car’s life as it gets older, and obviously, there are a host of significant other factors. 

But one thing remains the most essential: having fresh oil and doing regular oil changes. They may be boring, and they may be old school, too. But they matter, for the same reasons they always have. 

There are several reasons why, so let’s break them down. Some are timeless, but there are new factors that come into play with oil changes, so we’ll look at those as well. When we’re done you’ll come away with a complete understanding of the subject, and what you read here may even push you go head down to your local service outlet and get an oil change right away. 

The Basic Reasons Your Car Needs Oil

Let’s start with the simplest part of this question: Why does your car need oil? It sounds like a silly question, but a detailed answer is actually very revealing. 

Think two words—friction and lubrication. Friction between the metal parts of a car’s engine would destroy your engine in a very short amount of time, actually 30 minutes or so if you go totally without oil. 

Oil is also essential to properly cool a car’s engine. Many people think this task is handled by the coolant in the car radiator, but if the oil gets too hot it becomes impossible for the coolant to do it’s job.

Another reason cars need oil is to control the byproducts that are left by combustion whenever you run your car. These byproducts are destructive in nature when it comes to engine operation, and oil helps remove them and render them harmless. 

Finally, engine oil also helps clean the engine as a whole. It removes debris that can form metal deposits, and these can damage an engine to the point where it no longer functions. 

What is changed out in an oil change?

There are two main things that are changed out during an oil change: the oil filter, the oil itself. The oil filter is changed out to ensure that your car’s oil is clean. The oil is changed out because over time it can become sludgy and no longer do its job properly.

Of course, other items are adjusted, such as the oil drain plug which prevents oil from leaking out of your car, yet still gives the ability to easily drain the oil.

They will also be taking the oil cap off the top of the engine to pour the oil into the engine.

Thankfully, changing the oil in your car isn’t that hard! However I have found this is one of the main things that I have a shop do for me. It generally is only slightly more expensive, but is much easier. However if you are someone that likes to go DIY, this kit is a great place to start for getting the job done!

What are the Two Types of Engine Oil?

The oil used in car engines comes in two basic types—mineral oil and synthetic oil. Mineral oil is a petroleum product that is similar to crude oil, while synthetic oil was developed in a lab with the idea of providing the same kind of lubrication its petroleum cousin provides. 

So what’s the difference between the two when it comes to oil changes? Mineral oil is cheaper, but it doesn’t last nearly as long as synthetics, which are designed to go for several thousands of miles. In addition, synthetics consume less natural resources, and holistically speaking this helps counter their cost to at least some extent. 

Oil also comes in specific weights. This is important because it’s essential to match engine oil against the size of the engine. Car manufacturers design the engines in their different models and types to function with a specific weight of motor oil, and using a different type can cause poor fuel economy or even engine damage. 

Why are Oil Changes Necessary?

The answer to this one is also simple—wear and tear. The quality of engine oil tends to degrade over time, and when this happens the oil starts to struggle to provide lubrication, cleaning, and cooling, i.e., the jobs it was designed to do. 

The next question is obvious: How often does engine oil need to be changed? The answer to this used to be simple—every three months or every 3,000 miles, whichever came first. 

This recommendation eventually became a truism that was considered a basic requirement by most car owners, but the fact is that both the recommended interval and the mileage have changed considerably over time, especially during the last couple of decades. 

The reason for this change is the advancements that have been made in synthetics. Some can last as long as 10,000 miles between changes and continue to perform reasonably well during that entire period. 

As a result, the recommended window for an oil change has changed from 3 months to 6-12 months, and it’s not unheard of for cars using synthetic motor oil to go over a year between changes and not suffer significant damage. 

Frequently Asked Questions

What happens when the oil light comes on and off?

The oil light in your car is designed to come on when the oil level in the engine is low. This is usually because the oil has broken down and needs to be changed. The light may also come on if there is a problem with the oil pressure sensor. If the light comes on and then goes off again, it may just be a faulty oil light, but it’s always best to check the oil level just in case. If the light stays on, it means that the oil level is still low and you need to add more oil. If you keep driving without adding oil, you may damage the engine. So if you see that little oil light come on, don’t ignore it!

How long can I drive with change oil soon?

The answer is: it depends. If you’re just running errands around town, you can probably go a few more days before changing your oil. However, if you’re going on a road trip, it’s best to change your oil before you hit the open road. The last thing you want is to run out of oil or lose the proper flow of your oil in the middle of nowhere. So, when in doubt, change your oil.

Can you feel the difference after an oil change?

Depending on the make and model of your car, you may indeed notice a difference after an oil change. However, it’s also possible that you won’t notice any difference at all.


There’s a lot of relevant information when it comes to why you need oil and why you need to change it, but the bottom line is fairly simple. 

Follow the manufacturer’s recommendations for the weight and type of motor oil, and change it according to those recommendations as well. This will extend the life of your car, and give you the best possible performance, too. 

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