My car’s engine burns a lot of oil

We often get the question why is my car burning so much oil? The answer lies in the details, for instance we have here 3 different pistons from 3 different era. They are about a decade apart from each other. Take a close look at the oil rings on the pistons. The first one is the thickest at 3.98 mm, this one is the oldest piston. The next at the middle from a MINI, it is a little thinner.  The last one is the dirty looking one, which is covered in carbon at 1.98 mm and appears to be super thin.

BMW pistonsInternal Combustion Engine Pistons

That dirty looking piston with the super thin piston rings on it  from a 2013 BMW 328xi with the N20 engine. Why is it so thin you may ask?

The #1 reason  is to reduce friction and increase the fuel economy which has been legislated and called the CAFE (Corporate Average Fuel Economy in short CAFE). The manufacturers must comply with a mandated fuel economy which is for stage 1 we already passed in 2016 and the next stage is set for 2025. Today ICE (internal combustion engines in short) must leave up to strict fuel and emission standards, doing so the manufacturers are looking to maximize the ICE fuel economy by the means of minimizing the energy required to move the internal components.

My BMW Burns A lot Of Oil

This a phenomenon on all late model modern engines, so what can be done about it?

You as a consumer must stay on top of things for instance follow a schedule for your oil service based on your driving habits. Choose a knowledgeable service facility to help you reduce your engines oil consumption by using the best possible high tech motor oil for the application, this should be determined by experience not by convenience.

You also need to remember, to make your engine last, you must have it running at least half an hour to 45 minutes to be able to get the oil circulation heat up and perform a self clean internally. The low tension skinny piston rings will allow more water to condense into the motor oil, which will be accelerating the internal engine wear prematurely.

Internal combustion engine pistonsClick on the thumbnail to view bigger photo or visit our Facebook for more photos and information on BMW N20 engine issue.

How does it work? This is the chemistry, which makes your engine tick HC, (hydrocarbon) fuel when burns in the combustion chamber with O/2 (oxygen). It will create a by product H2O (water) that water or steam is visible in cold start say in -10C or bellow. That steam or water vapour is always present at all the time so some will pass by the skinny rings and will condense into the motor oil.

This has 2 effects, one it will dilute the motor oil, 2 it will sink to the bottom of the oil pan if the engine runs extremely short distances. This acidic water will sink to the bottom of the oil sump and at next cold start the engine will get water pumped to it’s internal components instead of motor oil, as we all know water is a terrible lubricant. The only solution, especially on the German vehicles, the operator, driver must heat up the oil extensively so the crankcase ventilation system can handle the excess water which gets vaporized and get send back into the engine combustion chamber and will be expelled in the process.

So in short as the saying goes, if you don’t use it, you will loose it. Perhaps should rephrase it, if you don’t use it long enough you may loose it a lot earlier stage than you should be, is the ultimate motto for this.

Any questions how may we help? Give us a call to: 905.795.0419!


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