Having a car that is excessively burning engine oil is not something you wish to experience. But before we get all pessimistic and elevate your worries to another level let us calm you down with some facts. A certain degree of oil consumption in your car is perfectly normal and it varies from car to car. If you are reading this and all you have to do is top off your engine oil level once during your oil change interval then there is absolutely nothing you should worry about. However, if you find yourself having to top off your engine oil multiple times in a few months, there is certainly something that is not working as it should.
We all dread the sight of a dry oil dipstick but it is not the end of the world. Here are all the signs and symptoms that your car is burning oil, how to prevent your car from burning oil and how to fix the oil burning problem for good.
Why Is My Engine Oil Level Decreasing?
Before we get into why your engine is supposedly burning oil, we should first rule out other reasons why your engine oil is disappearing. If your car is in relatively good condition and you make sure to maintain it regularly, then it is more likely that you are losing engine oil through a leak than by actually burning
How To Tell If Your Car Is Burning Oil (Signs And Symptoms)
If you notice that the oil level on the engine oil dipstick is lowering at an increased rate then yes, there is a chance that your engine is burning oil, however, that is not the only reason for disappearing engine oil. More typical symptoms of an engine that is burning oil include:
Blue exhaust smoke
Have someone sit in the driver’s seat and rev up the engine, when the car revs up, it will blow out smoke that will be blue and it will smell like burning oil. If you notice blue smoke, it is clear that your car is burning oil.
The engine has a rough idle and misfiring problem
This is an odd symptom but a really common sign that your engine is burning oil. If your engine tends to have a rough idle and it even happens that it misfires occasionally, it is highly likely that the engine oil which is being burnt during the combustion process is fouling your spark plugs. This leads to rough idling and misfires.
Take a look at the spark plugs
If you are a little car-tech savvy, you can easily remove one or more spark plugs to inspect their condition. A car that is burning oil will have dirty, oily, wet and sooty spark plugs that should in normal conditions be completely clean and dry. Replacing the spark plugs does not really make any sense before you resolve the underlying issue for your oil burning problem. New spark plugs on an engine that burns oil will eventually get destroyed again.
How To Tell If You Are Leaking Engine Oil
If your engine oil level is dropping but you ruled out all possibilities that your car is burning oil, then you are probably dealing with a serious oil leak that should not be hard to spot. Yes, the first symptom of an oil leak can usually be seen on your driveway. Oil marks that form under your car are a clear indicator of oil leaks. However, there can be oil leaks that do not reach the ground.
Open up the hood, take a strong flashlight and have a look around your engine bay. If any parts of the engine seem oily and wet it is clear that somewhere, somehow you are leaking engine oil. Oil leaks can also be caught on the engine protection cover below your engine so we recommend you take it off and see if there are any signs of oil leaks.
On rare occasions, you can actually smell oil leaks. A smell of burning oil underneath the hood of your car indicates that your engine oil is leaking onto one of the many hot surfaces of your engines, causing it to burn and evaporate. The smell of burning oil will be immediately noticeable but there will be no oil marks on your driveway or beneath the engine.
Your mechanic should easily detect any oil leaks each time you get your engine oil replaced. If there are leaks, make sure you take care of them as soon as possible before they develop into a bigger problem.
Normal Engine Oil Consumption
What Is Considered A Normal Oil Consumption Of Your Car?
No engine on this planet is made to be completely oil and gas-tight. This is why even the most sophisticated engine, such as those on your car has a certain tolerance of oil consumption that is considered to be normal. A small amount of engine oil will always be burnt in the engine but that amount should be burnt up at a slow and steady rate.
The majority of manufacturers of cars will consider burning more than 0,5% of oil consumption in relation to the actual fuel consumption. In other words, burning more than 1 quart or 0,95 liter of oil per 6400 kilometers or 4 miles is considered excessive. Keep in mind that performance vehicles, diesel cars and cars used for towing will usually consume more engine oil as they work with higher pressure. User manuals of modern cars often state that the engine oil consumption can be up to one liter per 1000 kilometers – even if this is rarely the case. With this information, however, the car manufacturers can get away with keeping possible warranty claims due to oil consumption at bay.
Oil consumption normally increases as cars age due to the wear and tear of the internal parts of an engine. Weirdly enough, modern engines tend to consume and burn more engine oil for several reasons. Modern engines have reduced tension and friction points in the engine in order to increase fuel efficiency. The reduction in piston ring tension leads to a higher oil consumption rate as more engine oil slips in-between the cylinder walls and pistons and into the combustion chamber. Additionally, lighter engine oil is being used to better tackle cold weather and to increase engine lubrication. However, lighter engine oil tends to slip into the combustion chamber easily which also leads to a higher oil consumption level.
Reasons For Normal Engine Oil Consumption
Some engines consume more engine oil due to their design and manufacturing tolerances. The driving style also has an influence on the oil consumption: The more sporty the driving style (up to high engine speed regions), the higher the oil consumption can be. Due to the higher pressure, more oil can get past the seals and into the combustion chamber (e.g. as blow-by gasses ), where it is also burned.
Oil consumption normally increases as cars age due to the wear and tear of the internal parts of an engine. Weirdly enough, modern engines tend to consume and burn more engine oil for several reasons. Modern engines have reduced tension and friction points in the engine in order to increase fuel efficiency. The reduction in piston ring tension leads to a higher oil consumption rate as more engine oil slips in-between the cylinder walls and pistons and into the combustion chamber. Additionally, lighter engine oil is being used to better tackle cold weather and to increase engine lubrication. However, lighter engine oil tends to slip into the combustion chamber easily which also leads to a higher oil consumption level.
The worse the condition of the seals (including the piston rings), the higher the oil consumption, since more oil can get into the combustion chamber here too. If the engine temperature rises, the viscosity of the engine oil decreases. It becomes “thinner”. If it becomes particularly thin due to high engine temperatures, more engine oil gets into the combustion chamber.
What Is The Reason For High Oil Consumption
We want to divide this section into two parts as there are many factors that affect high engine oil consumption. The first section will analyze the reasons for increased engine oil consumption and the second section will analyze how incorrect engine oil might affect the engine oil burning process.
Worn out engine components
- If the bearings of turbochargers have too much play, they no longer seal the impeller properly. Engine oil is drawn in and burned by the strong airflow. Excessively high temperatures in the oil return lines of the turbocharger can lead to oil coking and thus to clogged lines. The engine oil then no longer runs back easily enough into the oil pan and can flow past the impeller bearings due to the high pressure in the intake tract, which also causes it to burn. Causes of excessively high temperatures in the turbo area can be incorrectly routed and/or poorly insulated return lines, missing or poorly fitted insulating plates and a generally excessive oil temperature (which should be investigated).
- Relevant for older diesel cars: wear on the in-line diesel injection pump. During the pumping motion, engine oil can enter the working chamber and is then burned together with the diesel.
- Leaky intake: The air needed for combustion has a long way to go to the cylinders. Many hoses, connecting elements and seals lie along this path. If there are leaks here, unfiltered, dirty air enters the combustion chamber. The dirt contained in the cylinder causes mixed friction and thus increased wear on the cylinder, pistons and piston rings. This leads to oil consumption increasing over time.
- The valve stem seals are designed to prevent oil from entering the valve guide. If this seal no longer seals the gap well enough, it will enter the intake or exhaust tract.
- If the cylinder head was disassembled for repair work and not properly tightened during reassembly (torque and sequence of cylinder head bolts are very important), distortion of the components may occur. This can lead to leaks between the combustion chamber and the oil circuit. The oil enters the combustion chamber and is burned without any externally visible loss at the cylinder head gasket.
- Excessive pressure in the engine housing: During combustion, blow-by gases are generated in the cylinder (see above: Driving style). Excessive wear on pistons, piston rings and valves can cause the engine oil to be forced through the seals and co-combusted.
- Another problem is defective crankcase ventilation (PCV), which can cause the normal oil mist in the crankcase to enter the intake tract and be burned off.
- If fuel remains in the combustion chamber due to a fuel mixture that is too rich, a defective turbocharger or incorrect ignition timing, this destroys the lubricant film on the cylinder wall. The result is excessive friction, which wears out pistons, piston rings and cylinder liners. Diesel engines are not immune to this either: defects in the turbocharger or the injection system (injectors/high-pressure fuel pump) can cause a similar effect.
Poor oil selection and maintenance
- If the maintenance intervals prescribed by the manufacturer are not observed and exceeded, the engine runs on old, contaminated oil that is no longer as efficient as fresh oil. The lubricating effect decreases, which increases wear inside the engine and can lead to some of the problems described above. The cost of an oil change is small compared to the damage caused by premature engine wear.
- Incorrect or inferior engine oils can accelerate wear in the engine tremendously. This is especially true in extreme situations such as a cold start in winter or extremely high outside and engine temperatures. Therefore, obey the manufacturer’s specifications for the engine oil.
- The correct specification of the engine oil is more important than the price and measly savings. Especially with the introduction of the new 0W20 oils for certain modern engines, caution is advised: These oils can cause severe engine damage in older, unsuitable vehicles.
How To Prevent Your Car From Burning Oil
The easiest way to prevent your car from burning is to have it regularly serviced by a professional that is able to recognize early signs of increased oil consumption. The sooner you take care of the component that is causing the increased oil consumption. Use the correct engine oil and regularly check the engine oil level. Other than that, there really is not much you can do, use high-quality oil, have it replaced regularly and visit a professional service center.
What To Do If Your Car Is Burning Oil
If you notice increased oil consumption and can clearly rule out your own driving style as the reason, you should start troubleshooting the vehicle. A skilled mechanic will have no problems determining what the issue and the reason is for increased engine oil consumption. Fixing the problem can be as cheap as 100$ (replacing the PCV valve for instance) or it can cost more than your car is currently worth (3000$ or more for a complete engine rehaul).
Your mechanic will give you the estimate of how much the repairs will cost and based on that you can either go ahead with the repairs or decide to sell the car for a lower value since the engine probably needs extensive repairs.
Frequently Asked Questions
Is Engine Burning Oil Normal?
Yes, every engine burns a certain amount of engine oil. The exact tolerances are defined in your car’s owner’s manual. If you exceed those values, consult a mechanic.
My Engine Is Burning Oil What To Do?
First, make sure that there aren’t any oil leaks that caused the drop of engine oil level. After you have done that, consult a mechanic to identify the underlying reason for the increased oil consumption.
What Happens If Your Engine Is Burning Oil?
An engine that is burning oil will cause several other components like spark plugs, and DPF filters to fail. Your engine will eventually break down completely.
Can You Stop An Engine From Burning Oil?
You certainly can, one solution might be to start using appropriate engine oil. If that does not help, there is no magical solution to stop your car from burning oil. Extensive repairs are usually needed, consult a mechanic as soon as possible to prevent further damage.
Can An Engine Burning Oil Be Fixed?
Of course, it can. In some cases, minor repairs are needed (like a PCV valve replacement) but in other cases, entire engine overhauls are needed, it all depends on the reason for the increased oil consumption. But yes, all engines can be fixed.
Is It Bad For An Engine To Burn Oil?
Yes, an engine that is burning too much oil will eventually destroy other components of the engine like the turbocharger, spark plugs, DPF filters, etc.
How To Reduce Engine Burning Oil?
There is no magical solution for stopping your engine from burning oil, minor or extensive repairs are needed. However, in some cases, using a slightly thicker engine oil might help. Do not use thicker oil without a consultation with a mechanic or a certified technician of your car’s brand.
What Does Burning Engine Oil Smell Like?
Well, it smells like burning oil. You will know exactly what we mean as you inhale the scent of burning oil. Certain people also say it smells like sulfur.
What To Use To Stop An Engine From Burning Oil?
There is nothing you can use that will stop an engine from burning oil. A thicker oil might help in some cases but at the end of the day, certain minor or major engine repairs will be needed.
When Does The Engine Oil Light Come On?
When there is not enough engine oil in the engine. A malfunctioning engine oil level sensor might also cause the check engine oil light to come on. Verify the oil level with a dipstick if you have one.
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