4 Bad Things that Will Happen if You Don’t Change Motor Oil

Changing motor oil is mandatory for every car after a certain number of miles. New gasoline cars need an oil change every 5000-7000 miles while diesel every 7000-10,000 miles. Failing to do so would not just make your engine run harsher, it would ruin it. 

Here is a list of 4 bad things that will happen if you don’t change motor oil.

What Will Happen if You Don’t Change Motor Oil?

Your engine needs oil to run smoothly, cool, and efficiently. Not changing oil would result in your engine running rough, hot, and inefficient.  

Engine oils are used to lubricate the engine. As your engine is having constant combustion with the piston going up-down 600-1000 RPM even at idle creates a lot of friction. It also creates a lot of heat, and it is the engine oil that takes care of both.  

With time the engine oil starts to get dirty and sluggish. The thicker it gets the less lubrication it can provide which leads to the following problem. 

Also read: Why are Diesel Oil Changes so Expensive? (Explained)

1. Increased Wear and Tear

Increased wear and tear are the first after effect of bad engine oil. Since the oil is responsible for handling the lubrication. As it gets thicker, it fails to reach all parts of the engine, failing to lubricate it properly. This results in more wear and tear of engine components due to the friction it causes. 

Engine oils are not just simple oils, they have many additives to handle many jobs. For lubrication purposes, you have additives like antioxidants, anti-wear, rust-corrosion inhibitors, etc. 

With the oil moving all around the engine, it constantly applies a layer of these additives to protect engine components. Over time, as the additives are consumed and the oil is left filled with impurities, these impurities are like very fine grains of sand rubbing between parts of the engine, heavily increasing wear and tear.  

2. Bad Engine Performance with Reduced Efficiency

Engine oil also has detergent as an additive to keep engine parts clean and safe from deposits. It also protects any acid formation inside the engine due to its alkaline nature. All of these keep the engine parts clean while the lubricants make it run smooth. 

But as the additives are consumed over time and oil is left with impurities, it does not just start to deteriorate the engine components. It also makes it rougher because the parts have to fight against those impurities to move. 

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The dirty thick engine oil creates drag and friction, forcing the engine to work hard. As a result, you get very bad engine performance and even worse fuel economy.

3. Overheating, Leading to Engine Failure

One major job of the engine oil is to keep the engine cool. Yes, you do have coolant, but the oil is also used to reduce engine temperature, because, unlike coolant, the engine oil rotates all around the engine among both the big and small moving parts. 

As the oil rotates, it collects heat from the engine, goes to the oil pan where it’s cooled down using oncoming air, and then pumped back again. But when the oil gets old, it also gets thick due to which its heat retention is increased. It gets harder to cool the oil down and the engine runs hotter. 

The hotter engine soon gets overheated which can blow your head gasket, crack your engine block, melt your engine parts, and can also go BooM.    

Also read: How to Effectively Warm up Diesel Engines

4. It Voids Warranty

Not getting your oil change or your vehicle serviced at the stated time will result in your warranty getting voided. The manufacturers ensure the health of your vehicle by performing maintenance at certain intervals of time. 

By not getting this maintenance done, you are intentionally putting your vehicle’s health at risk. And if it results in a major failure, it won’t be the manufacturer’s fault anymore, meaning you will have to be responsible for all the maintenance charges.  

Also read: Oil Pressure Engine Off Warning. How to Fix it?

How Much Does Not Changing Motor Oil Can Cost You?

Not changing your motor oil will lead to engine failure. Depending on the damage it does, you can pay between $1000-$10,000 in repairs.

Bad engine oil leads to a host of possible scenarios. Assuming that you refuse to get an oil change entirely, the first cost increase would be due to extra fuel consumption. Then it will lead to a voided warranty. 

Depending on your vehicle, that can be a loss of $1000-$4000 because that is how much it cost for an extended warranty. Losing the manufacturer warranty would be a loss of the same amount. 

Moving on to the engine-related issues it would cause, the most likely one is a blown head gasket. While the gasket is only between $500-$1000, the complexity of the job adds labor cost between $700-$1200. 

If you get your cylinder head cracked, expect to pay around $500. But if it results in an engine seize, you might have to replace your whole engine. That generally costs between $3000-$5000 for daily driving cars. All because you refused to have a $100 oil change.

Also read: Does Engine Oil Brand Matter? Can You Buy a Random Brand?

How Often Should You Change Motor Oil?

You should change your motor oil between 5000-7000 miles for a gasoline engine, and between 7000-1000 miles for a diesel engine when using synthetic oil.

Both gasoline and diesel cars use different types of motor oil. You also have the option to choose between natural engine oil and synthetic engine oil. The oil change interval also gets reduced as the vehicle gets older. 

But you don’t have to worry as all of these are mentioned in your user manual. Generally, an oil change is recommended at least once a year or ideally every 6 months

As for how many miles here is a list of recommended intervals.  

Engine TypeNatural/Conventional Motor oilSynthetic Motor Oil
New Gasoline Engine5,000 miles7,000-10,000 miles
Old gasoline engine (50,000 miles+)3,000 miles5,000-6,000 miles
New Diesel Engine5,000-7,000 miles7,500 miles
Old Diesel Engine (80,000+)3,000 miles5,000 miles

Remember that these numbers vary depending on how you drive, how far you drive, the weather and situation you drive in, etc. Constantly checking your engine oil level and oil quality should take priority over time or distance traveled. 

Also, always get your oil filter replaced when having an oil change. 

Can You Just Add Oil to Your Car Instead of Getting an Oil Change?

Yes but not forever. You would need to change the oil after some time. That’s because the slugging oil over time might clog the filter, the oil pump, and might result in an engine seize.

The motor oil does not only get dirty and sluggish, it also evaporates with time. The increased density with some vaporization results in reduced engine oil levels over time. Adding extra oil would bring your oil level to optimum, which is a lot better than not having an oil change at all. 

But the sluggish oil would still be in rotation inside your engine. And as add more oil the more impure oil would be created to a point where it would clog the oil filter, the oil pump, and result in an engine seize. 

So while you can add oil to keep your engine running smoothly, not getting it changed would eventually turn into a disaster. 

Also read: Can a Car Engine Explode? How to Prevent it?

How Do I Know When was My Last Oil Change?

If you got an oil change at your dealership, it would be mentioned in your service book. Otherwise, look for the engine oil light sign on your dashboard. 

If you are getting your vehicle maintained regularly at your dealership, the service book of your car would have all the records of it. You can just look through it to check the last date of service. 

But if you don’t then you have to do it manually.

How to check engine oil levels manually? 

  • Start your engine and wait for the oil to circulate. 
  • Then pop your hood, take out the dipstick, clean the oil off it. 
  • Re-insert the dipstick and take it out again to see the oil level.  
  • If the oil on the dipstick is towards the lower side among the markings, that means you need an oil refill. 
  • But if the oil is dark and thick in density similar to Tar, you need an oil change.  

Can I Change Oil by Myself?

Yes, you can. After all, about 72% of Americans do their car maintenance themselves. Changing engine oil is a simple process that only takes about 20-30 mins.

Once you have confirmed you need an oil change, the things you would need are:

  • Engine Oil
  • Oil filter
  • Oil pan
  • Oil filter wrench
  • Funnel 

How to Change Motor Oil?

  • You start by locating the drain plug under your car.
  • Now place an oil pan under the drain plug.  Open the oil filler cap located in the engine bay. Then open the oil drain plug.  
  • Now locate the oil filter and unscrew it with the oil filter wrench.
  • Screw the new filter and then screw the drain plug once all oil is out. 
  • Now add the new motor oil to the engine using the funnel. Keep the process slow.  
  • Make sure to only add the required amount. Don’t add extra. Read the user manual for precise quantity. 
  • Once the new oil is refilled, start your engine and let it idle for 2-3 minutes.