A Comprehensive Guide on Why Cars Burn Oil


At some point, your car might start burning engine oil and you might ask yourself why cars burn oil? Is it normal? It could be normal with some car models, but most of the vehicles are designed to run without burning oil. If you notice that your engine oil level is low even though you changed it on time, this could be an indicator that there is something wrong with your vehicle.

Why Cars Burn Oil

There are 5 main reasons why cars burn oil: damaged combustion rings and oil control ring on pistons, damaged valve stem seals, you are using wrong engine oil, aggressive driving and overall excessive engine wear.

Why Cars Burn Oil

If your vehicle is burning oil, it doesn’t have to mean that you are looking at a huge mechanical bill. It could be an easy fix, but you must get it checked. Here are the top 5 reasons why cars burn oil:

1. Damaged Combustion Rings and Oil Control Ring on Pistons

One of the most common reason why cars burn oil is damaged combustion rings and oil control ring on pistons. The piston has two combustion rings which are of equal thickness. They do the heavy lifting of sealing off the combustion side from the crankcase side. Next there is the oil control ring and it’s responsibility is to scrape the cylinder walls of oil as it’s going down. So, it separates the oil that’s lubricating the bottom part of the piston from escaping back into the top part of the piston where it’s going to be combusted. When they get damaged, the seal is broken and oil can enter the combustion chamber.

A Comprehensive Guide on Why Cars Burn Oil

The way that combustion works is the piston moves up and down in the cylinder wall. It is very important that the interface between the cylinder walls and the piston rings are completely sealed. So, when combustion occurs at the top, all of the energy is transferred into pushing the piston down and it doesn’t escape into the crankcase.

A Comprehensive Guide on Why Cars Burn Oil

The first major flaw of the engine design is that it is operating too hot. If your engine was designed to operate at 120 degrees Celsius and at some point it gets up to 160 degrees Celsius due to some malfunction, the oil is going to start to break down. It will cause carbon deposits on the piston rings. The oil control ring is supposed to collect all of that excessive oil and push it through some tiny holes inside of the piston head.

A Comprehensive Guide on Why Cars Burn Oil

2. Damaged Valve Stem Seals

The second reason why your engine car burns oil will actually come from the cylinder head itself. Basically the entire cylinder head is covered in oil while the engine is running. If you look closely inside one of the valves here you can see that they are basically an oil seal. The valve rides up inside and separates the oil from the top half of the engine from the bottom half of the engine which has the combustion.

What happens is your engine ages and all of the seals become a little bit harder and more brittle. They’re gonna start to leak oil. Typically overnight you’ve got a pool of oil sitting around that valve. When you start the car it’s just gonna start seeping down into your combustion chamber. Once you turn on the engine you will see smoke out of the tailpipe which means that that oil has been burned.

Changing your valve stem seals requires you to pull the entire engine head off because you’ve got to get each and every one of these valves off so you can change that seal. It is quite a labor-intensive work and usually at higher mileage cars it’s not worth it.

3. Using Wrong Engine Oil

The engine oil that you are using must have specific approvals from your manufacturer. The diesel and gasoline engines use different engine oils. If you are using the wrong approvals your engine might start burning oil because the oil that you put in might not be thick or thin enough. With the lack of lubrication, the metal components would rub and wear faster than normal.

4. Aggressive Driving

The way you drive can affect the engine oil consumption . If you have a diesel engine and you constantly drive above 3000 rpm progressively from a longer period of time. The engine oil heats up and it gets thinner and it finds its way into the combustion chamber and gets burned. This happens mostly on drift cars. If you only drive around town with low rpm, the engine oil doesn’t heat up that much and it won’t consume oil.

5. Too Much Wear On The Engine

The last reason why some engines consume oil is because there is too much wear on your engine. When you have a lot of wear in your engine, the engine oil seals get damaged. The oil will pass through those oil seals and it will penetrate to the combustion chamber and the engine will just burn your oil. This usually happens when you have lots of miles or kilometres. The thing with the older engines is that the cost of the repair is very big. It’s better if you just add oil as you drive. You would notice a blue or white smoke coming from the tailpipe.

How To Prevent Your Car From Burning Oil

There is an easy way that you can prevent engine oil consumption. Change the oil regularly and make sure that you add the correct oil and oil filter. Also, run diagnostics on your vehicle. I got ordered an OBD scanner from amazon long time ago. I scan my vehicle every month and that’s how I stay on top of the problems. A simple scan can get you to act fast before more damage is done to the engine.

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