Why my car smells of burnt oil

burnt oil

It often happens that we are on our way to our destination and we begin to perceive a strong smell of burnt oil that, on several occasions, is accompanied by smoke. This happens normally when there is a leak that goes to the engine and it burns and although it is not given importance, it is a fault that must be checked by a specialist.

Keep in mind that many defects in the vehicle may be causing this particularity and if you have ever wondered why my car smells like burnt oil , in a COMO we explain it to you.

What is the oil path in the car engine

the burnt oil

Before understanding any failure, it is important to know how the oil works in the car and what its route is ; Knowing this we can detect quickly in case it happens unexpectedly.

The oil is deposited in the crankcase, passes through the oil filter and this is responsible for cleaning it of any impurity it contains. After this is driven by a pump, causing it to travel the entire lubrication circuit, here there is a valve that is responsible for regulating the pressure and maintain it throughout the journey to control the viscosity of the oil and all its changes. After all this process, the same oil goes back to the crankcase to cool down and start the journey shortly again.

In this process valves and pistons are involved, which close and rise, this generates a mixture of gasoline with oxygen creating combustion and when this happens, the oil begins to burn or at least the layer that is created; The problem arises when the oil burning is excessive and begins to create smoke or an unusual smell, from here, we will look for where in the entire route the fault is located. Keep reading Top Five Car Tracking Devices

Smell of oil burned in the car by a leak

Oil leaks in the car are one of the most common faults and can occur properly in the engine or in the catalytic converter or the exhaust manifold. This small error can be due to poor condition or damage to the cover of any of the valves, if there is a break, oil wells are generated, allowing the involuntary exit of oil to the collector and, consequently, burning the oil in the car. leaving an extremely strong smell.

This can be solved with the change or repair of the covers on the covers if it is in perfect condition, otherwise they should be replaced and replaced with new ones. In a COMO we tell you more about what to do if the car loses oil .

Faults in the oil filler cap

car smells of burnt oil

This is more common in cars whose engine is very old . These can present wear on the piston rings , causing the pistons to absorb much more oil than they should; It burns here and is returned already burned.

Remember that there is a valve that is responsible for ventilation of the crankcase, area of ​​the vehicle where the oil is deposited; When the smoke does not suck properly for another burn, the oil filler cap is passed.

As we commented before, it usually happens more commonly in vehicles with many years of antiquity, however, there are other failures such as clogged valves or with a lot of wear that generate a row of errors in the ventilation of the crankcase and the cover itself.

Failure in valve seals

The valves are responsible for propelling the oil all the way from the crankcase to its return, when there is a problem or breakdown in the seals of these, the oil begins to have difficulty moving to the combustion chamber and is known to happen because it generates the famous “blue smoke” at the time of starting the car or when it accelerates.

With regard to the smell of oil, it may be due to a filtration caused by the same failure of the valve seals ; These small drops fall to the engine and as it is hot, it burns generating a highly unpleasant odor.

Keep in mind that having the car with low oil levels can cause many faults in the filter, valves and the engine if it is not well lubricated.

That is why the first failure you notice in your car, it is important to take it to a professional mechanic to fix the problem in time and not generate a worse or in the worst case, permanent damage to the piece. It is also important to be aware of when the revision of each certain mileage is due and to do its maintenance to avoid accumulation of oil, dust or any other damage.

Oil problems in the engine

the car smells of burnt oil

In this case, do not be alarmed yet and take your time reviewing. Probably when you raise the bonnet there is smoke coming out of the motor bay and it is most likely that it is leaking oil somewhere and a little this falling into the exhaust manifold or the catalytic converter. Precisely the gaskets of the valve cover are quite susceptible to this problem, because oil wells are formed along its inner edge that go to the exhaust manifold.

The road that runs through the oil in the car engine

The engine oil is deposited in the crankcase, from where a pump provides the necessary pressure to travel the lubrication circuit, passing before the oil filter, which will eliminate much of the impurities.

A regulating valve, which is sometimes inside the pump itself, is responsible for maintaining a constant pressure, which is essential due to changes in the viscosity of the oil. Later, the oil returns to the crankcase, where it cools a little, to go through the circuit again.

However, during the compression phase, when the valves close and the piston rises, the mixture of air and gasoline is compressed to reach combustion. At this point a spark is produced and the mixture is ignited by pushing the piston down. Then part of the oil film that had formed will be burned. This means

that every engine burns oil, but within certain limits. If the engine burns much more, you smell oil and see smoke, it is because there is a fault at some point in the circuit.

What can cause the smell of burning oil and smoke in the engine?

If you smell burning oil , it is likely that due to a leak, a little oil has fallen into the exhaust manifold or catalyst. Perhaps it is due to the fact that the valve cover gasket is in a bad state, since oil wells are usually formed on the inside edge that can end up in the exhaust manifold.

However, smoke in the engine can also be caused by problems in the oil filler cap , which is common in older engines. When the piston rings are very worn, the pistons suck oil into the cylinder, where it burns. If the crankcase ventilation valve does not suck in the smoke to burn it again, it goes beyond the oil filler cap . This problem is common when the tube or PCT valves are clogged or worn.

A problem with the valve seals will also prevent the oil from going down into the combustion chamber, which causes blue smoke, especially when starting the car. The smell of oil can also be caused by a slight overflow absorbed by a hot part of the engine or even due to too low a level of car oil.

Why should you immediately take your car to the workshop?

burnt oil

When a large amount of oil arrives in the combustion chamber, deposits begin to form, both in the spark plugs and in the piston and in the valves, to such an extent that the reading of the oxygen sensor is altered and the catalyst is clogged.

These carbon deposits will also cause a loss of compression and break the oil film that should adhere to the cylinders, so not only will you experience a considerable loss of power but also subject the engine to accelerated wear.

To avoid the accumulation of burnt oil in the engine , it is best not to neglect the preventive maintenance of the car. At Euro master we can check the oil level, make an oil change when the time comes and check that there are no leaks in the system.

Finally, the smell is quite similar to when tar or asphalt are exposed to many hours of sun. You do not have to have a very fine smell to detect it, it just appears and you know that the problems started. Sometimes it even comes out smoke and it is better to stop and take a look. car smells of burnt oil and the presence of smoke in the engine are signs that no driver should ignore. In fact, the ideal is to go immediately to the nearest workshop so that a professional can detect and solve the cause of the problem.

Author: Roger Walker

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