Why your engine consumes more oil as its mileage increases

To avoid severe engine damage, you need to top up engine oil more frequently. PHOTO/Roland D. Nasasira

What you need to know:

Burning oil is a common problem, but when it is ignored, it can lead to costly damage to your car’s engine. Common culprits that result in burning oil include worn valve stems, guides and seals, and piston rings, all of which can allow oil to seep into combustion chambers.

In 2021, Harunah Kiyemba bought a 2004 Toyota Rav4. Its mileage was in the range of 110,000km and was running on an engine overhaul warranty. At the time, he would do an engine oil top-up once before routine service after every 5,000km.

Three years later, much as it offered fuel economy, Kiyemba’s Rav4 developed faults he did not expect to have started in such a short time.

“It was consuming oil and fuel at a very fast rate. I contemplated buying a new engine and selling the car. Before regular service, I would have to top up engine oil three times. I would do an engine oil top-up on Sunday and it would be depleted by Thursday. I was spending Shs160,000 on oil alone before service that cost Shs150,000,” Kiyemba says.

“With these expenditures, I knew I was destined for more mechanical problems and decided to sell the car after it reached 180,000km. Besides, I researched and discovered that some models and other cars of the same brand with similar engines start consuming engine oil when they exceed a mileage of 150,000km. I had also been warned about the possibility of engine knocks if I did not make it a point to check engine oil levels daily,” he adds.

What experts say       

David Nyoike, the aftersales manager at Nissan Motorcare in Kampala, says there are several causes of increased engine oil intake in your car. First, as the car engine ages, you have to constantly check and ensure you do not have any oil leakages.

Secondly, there is the aspect of wear and tear within the engine cylinders where you get the piston rings and the gaps increasing over time.

“As a result of wear and tear, you have burning of oil as the vehicle is running. Oil burning, which is normally evidenced by the release of blue smoke from your exhaust pipe, means your vehicle is burning oil and there will be a higher rate of oil consumption. The wear and tear of piston rings is also accelerated and this normally is an indicator of poor car maintenance,” Nyoike explains. 

‘‘Sometimes, it could be because you are using the wrong oil type. In most cases, most of you go to fuel stations and have an oil change done without finding out what type of oil was put in your engine as specified by the manufacturer. Besides, your car service intervals have to be done correctly with the right engine oil, used in the engine to ensure you have optimum engine performance,’’  he adds.

Right, wrong oil

The differentiation between the wrong and right engine oil is always on the user or owner’s manual on every car, even with the used one you buy from the bond. What you have to remember is that most vehicles from bonds are from countries with extreme weather conditions such as winter. You have to look at the back of the user manual carefully because it not only gives you oil specifications but also the oil to use in a given weather or climate condition. If in doubt, it is advisable to consult an authorised dealer in the market.    

“If you use the wrong oil type, you will not get optimum engine performance. Most of the new-generation vehicles on the market use synthetic oils. If you use mineral oils, something that happens a lot at fuel stations and informal garages because you are saving money, it will cause high engine oil consumption. Engine performance will also be affected and the wear and tear in the internal components will increase because oil is not lubricating the engine components as it should be,” Nyoike explains.


Most, if not all new-generation engines, generate a lot of heat to be efficient. For example, most car manufacturers are downsizing to smaller engines. For instance, a vehicle that should ordinarily have had a 3000cc engine will have a 2000cc engine. What manufacturers do is put a turbo on the 2000cc engine. If the maintenance is not followed and respected as per the manufacturer’s recommendations, it will lead to increased oil consumption because it means you are experiencing more wear and tear in the engine due to wrong and or poor routine maintenance. As far as engine performance is concerned, you start experiencing increased oil consumption that every time you go to a fuel station, you, as Kiyemba, will need an oil top-up.

Most cars on the market communicate to drivers about aspects such as engine oil. When you go to refuel, do not put anything else. If the oil levels are low, visit your service dealer to have it checked.

“The habit of driving to a fuel station and the pump attendant opens your bonnet while you are on the phone and tells you that you need an oil top up and you have no clue what goes on in the engine is wrong. If you are driving a BMW and you use mineral oil, this will be the start of your journey to increased oil consumption and a messed up engine. Seek to understand why anything should be done on your car before agreeing to oil top-ups,” Nyoike advises.

Car engines are designed to run up to 500,000km and beyond without being tampered with. To achieve this, you must exercise car service discipline as per the manufacturer’s standards. When you see blue smoke coming out of your exhaust, if you can smell it, you will soon also smell burning oil. It is a sign that you are consuming oil that could be on the higher side. It also means oil is going to the engine combustion chamber where it should not be.

What is normal?

According to www.cars.com, as a rule, most engines with fewer than 50,000 miles should not use much more than a quart (1.13 litres) of oil between oil changes. If an engine requires a quart every, say, 3,000 miles or less, that could be a sign of a leak or of internal engine problems, such as worn valve guides, piston rings, or any of several different types of seals. Once an engine gets beyond perhaps 75,000 miles, and certainly past 100,000, increased oil consumption should be expected.

In addition, many newer engines use thinner, lower-viscosity oil. Because these oils are thinner, it is easier for them to slip past gaskets, seals, and rings that have worn even slightly over time, thus increasing oil consumption.