Bubbles In Engine Oil

Whenever there is unusual turbulence felt by the crankcase of your engine, there will be frothing of the oil and bubbles will be formed due to the same. When oil is put into the tanker, it is stable but due to the rigorous motion, there is a lot of movement as well as turbulence and vibrations felt by the oil in the crankcase which results in the formation of bubbles and froth.

This whole scenario is probably very harmful to your oil as it gets aerated and is churned. The formation of bubbles results in its excessive oxidation which in turn is responsible for decreasing its lubrication properties. If the oil will lose its lubricating properties, the hydraulic system will suffer failure.

Several causes can lead to the formation of froth and bubbles in engine oil. In this article, we will be discussing the same and will also be providing you with certain methods and tricks that can be used by you to ensure that there is no failure of the hydraulic system and the engine can function smoothly.

Causes of the formation of bubbles in engine oil

Water contamination in the oil

When there is water mixed in the oil by any chance, the oil gets contaminated with the water and there are several issues caused due to the same. There are bubbles formed on the surface of the oil that results in an increase in the viscosity of the oil and a decrease in its lubricating properties. There is also a loss of the film strength and this one major factor that is required to keep the parts apart and well lubricated. The presence of water in engine oil and also adversely affect the base oil and can result in processes like aeration, hydrolysis, and oxidation.

Mechanical issues with the oil

When the engine oil is filled, if there is a lot of aeration of the same, this is termed as the mechanical issue of the oil. Aeration of oil in the crankcase results in the formation of bubbles and froth. Too much aeration of the oil can also cause it to lose its lubricating properties and this can damage the engine as well. Mechanical issues with the oil need to be avoided to ensure that there is no aeration of the engine oil that might affect its performance.

Presence of solid contaminants

The presence of excessive solid contaminants in the engine oil leads to an increase in the value of the friction coefficient. This means, the friction power of the oil decreases which in turn makes the surfaces rough and dry. The turbulence caused due to the same also results in the formation of the bubbles that are then responsible for completely decreasing the lubricating properties of the engine oil. The accuracy of the lubrication given by the engine oil is decreased largely due to the presence of solid contaminants.

Overfilling of the sump

If the sump engine is overfilled with the oil, and there are splashes while this process is being carried, the formation of the bubbles is just unavoidable. It is important to fill the sump pump below the brim to make sure that there is no overfilling and formation of froth over the engine oil or else it will damage the engine and will not perform well itself as well. The bubbles need to be avoided as much as possible to make sure that the engine oil can deliver just the right amount of lubrication needed.

Presence of grease contaminants in the oil

The presence of any greasy substance in the engine oil will also contribute to degrading its quality. If there is a contamination of the oil with greasy contaminants, there will be a formation of bubbles as well as froth and this will lead to the reduction of the lubricating power of the oil. Greasy substances can destroy the quality of the base oil and can make it non-lubricant with time if not taken care of. Grease contaminants should not at all be allowed in the engine oil if you want to keep it froth-free and want it to provide the parts with proper lubrication.

These are a few reasons or causes of why there is a formation of bubbles or froth in the engine oil.

Bubbles In Engine Oil

The solutions for the occurrence of bubbles in engine oil

Check for the foaming

If you are seeing the formation of bubbles in your engine oil occasionally, do not avoid that at all. This is because it can deteriorate the working of your engine completely. Instead, you need to conduct a testing process for the same and see if there is a lot of frothing and foaming of the oil. If the answer is yes, you need to apply methods to control it and cure it completely if you want that your engine should work perfectly for a long time.

Go for the partial drain process

Once you notice that there is a formation of excess froth and bubbles in your engine oil. You can at first try the very basic method to solve this problem. You can go for the partial drain and refill process. In this process, you need to filter the engine oil partially and refill the same carefully. This is one of the methods that can help you in getting rid of the formation of bubbles in the engine oil.

Change the oil

Another straight option to deal with such a problem is to change the oil. But, this can be one expensive option as well as you will have to change the entire amount of oil in the tank. This process can also be very tough on the pocket if there are large volume systems. Although, this will give you the surety that there will be no harm done to your engine and that it will work well. If you do not want your engine to get damaged and want to save yourself from an extremely expensive purchase, you need to change the oil right away and get rid of all the damaging issues related to the same.

Lubrication reconditioning

The process of reconditioning the lubricants is a temporary solution and might not work well always. But, it is one of the easiest ways to deal with a little frothing and bubbling of the engine oil. In this process, the contaminants present in the engine oil are removed and the additive system of the same is regenerated or refurbished. This is one method that can be implemented as a solution for the light foaming of the engine oil. The conditioned lubricants will behave well when refurbished in the engine oil. The removal of all the types of contaminants will also increase the quality of the oil.

Manage contaminants

If there is a presence of a lot of contaminants in the oil, the quality of the same will get decreased. Therefore, if you can manage the contaminants of the engine oil that are present in it, you will be able to increase the quality of the oil. Especially, if there are water and solid contamination in the engine oil, you need to concentrate on managing them and do not rush for filtration. This is also because there are a few engine oils that tend to lose their lubrication because of the fine filtration process.

Fluid identification

If the foaming on the engine oil is a result of the cross-contamination of oils in the tank, you can go for the fluid identification process. The color codes of the various types of oils can be identified and the process can be implemented. This method is highly applicable if there are contamination and mixing of the various types of oils in one. This can help in the cleaning of the engine oil and it will work well with delivering proper lubrication.

Removal of grease contaminants

If the formation of the bubbles or the foam is the result of the presence of greasy contaminants. You can calculate the relube frequencies and quantities and remove them. The presence of grease in the engine oil tends to affect its lubricating properties badly. This is why it is important to calculate them and eliminate them from the oil completely.

These are a few effective ways that can be used to handle the problem of the occurrence of bubbles and froth in the engine oil.


The presence of bubbles and foam in the engine oil is an indicator of the bad quality of the oil. If there is a lot of foaming of the same, the quality of the oil will be degraded and it will tend to lose its lubricating properties as well. This is why this issue need not be avoided at all. If you want your engine to perform well and not get damaged due to the frothy engine oil, you can follow any of the given ways and deal with the situation. 

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