With today’s advances in fuel economy in new BMW models, those of us driving older models will try almost anything to squeeze out a few extra miles per gallon for our daily drivers. Keeping the tires properly inflated, ensuring fresh synthetic oil is flowing through the veins, and rebuilding those vanos units are the tried and true methods for maintaining better fuel economy. 

Once in a while though, we come across some products that sound too good to be true. Cynics will refer to them as snake oils, but are they really that bad? Liqui Moly has manufactured oils, treatments and lubricants for decades with an excellent reputation for creating motorsport products that work as promised. I have tried some of these inexpensive oil and fuel treatments recently to see what all of those 5-star reviews on Amazon are all about.

The first product I tried is Liqui Moly’s MOS2 anti-friction treatment. The test vehicle is my 2001 530i sport with the 3.0 liter, double-vanos, M54 inline six cylinder engine. It was poured into the crank case which held Castrol Edge 0W-40 fully Synthetic oil.

Does Liqui Moly MOS2 improve fuel economy by reducing internal engine friction? In this episode, I test out the MOS2 engine oil additive in my E39 530i for over 200 miles. So, does it work? Watch and find out:

Maybe this particular engine treatment needs some more mileage to see what it’s really capable of, in order to fully coat all of the internal engine components. To learn more about this product, click here to buy now on Amazon.

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Have you tried any oil additives that work for you? Let me know in the comments below along with any improvements in MPG you saw, and the model BMW you drive!