Mazda Long Life vs VMPAUTO GL-5 75W-90

May 28, 2024
8 min read
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Friends. Those who follow our blog, probably remember the story about how a trivial question from a car enthusiast on selection of oil in the gearbox of Mazda CX-5 led to a kind of investigation. Then in attempts to find the characteristics of Mazda Long Life Hypoid Gear Oil SG1 we dug through a lot of reference books, but there was no clear understanding of the picture. According to one data, the oil was supposed to be GL-5 80W-90, according to others – GL-5 75W-85. As a result, we decided to drain the original oil from the gearboxes of a similar fresh car and analyze it thoroughly. Such a car was found.

The oil was drained very dark.

Already when draining the oil we were strongly alarmed by the fact that the oil on the car with a mileage of only 27000 km was quite dirty. Moreover, the magnetic plugs, designed to collect wear products, were literally covered with small chips.

The drain plug was literally covered with metal shavings.

But the most interesting thing was ahead of us. The laboratory analysis showed that at 100°C the oil viscosity is 8.973 cSt, which corresponds to the API 75W-80 viscosity class. This means that the gearboxes were filled with the wrong oil, which is not specified in the recommendations.

It was decided to recheck the result. It so happened that another employee of the company had exactly the same car, but with much higher mileage. The oil in the gearboxes of this car had not been changed from the factory. Analysis of the oil sample from this car showed exactly the same picture. The gearboxes, judging by viscosity, were filled with 75W-80.

Oil is rife with wear products.

In addition, elemental analysis showed that the amount of wear products in the oil was approximately the same in the car with 27000 km and in the car with 106000 km.

As a result, the oil in both cars was changed to fully synthetic GL-5 75W-90 produced by our company. Then we promised to take oil samples again after some time and share the results with you.

Synthetic oil VMPAVTO GL-5, 75W-90 was filled into the gearboxes of the vehicles.

And this day has come. One of the cars, the one that at the time of sampling had a mileage of 106000 km, had run another 30000 km on our oil for six months.

The first thing we paid attention to, of course, was the cleanliness of the oil. We cannot say that it remained in pristine condition, but it was much cleaner than what we drained the first time.

Already when draining it was visible that the oil had hardly changed color.

If you don’t know, you might think it’s fresh oil. However, it has been running for 30,000 km.

Plus there was virtually no metal impurities in the oil. Then iron particles were clearly visible at the bottom of the container. This time metal powder was present only on the drain plug magnet.

Magnetic drain plug. There are practically no wear products.

Comparison of the amount of wear products on the magnetic plug.


We were also pleased with the laboratory analysis. The oil remained within the tolerance limits. That is, it did not fall apart, and its parameters fully correspond to the parameters of new oil. Viscosity of oil from the front gearbox at 100°C was 13.48 cSt and 13.92 cSt from the rear gearbox, which is quite within the parameters of 75W-90 oil. Note that viscosity of new oil at 100°C is 14.3 cSt.

Oil analysis was done on an atomic emission spectrometer.

As for wear, it has decreased. In the front gearbox, the iron in our oil became 124 ppm versus 172 ppm in Mazda Long Life Hypoid Gear Oil SG1. In the rear gearbox the changes are more striking: 100 ppm in our oil versus 264 ppm in Mazda Long Life Hypoid Gear Oil SG1.

Table comparing oil viscosity and the presence of wear products in them.

The drained oil was re-filled into the gearboxes and the vehicle continued operation. We plan to perform another oil analysis during the scheduled oil change when the oil has covered 60000 km. We will share its results with you. Follow the publications.

As for the second car, at the time of publication, it has accumulated about 7000 km on our oil. It is too early to make any serious conclusions on such a small mileage. Let’s say only one thing. We have analyzed this oil as well. If you will be interested, we are ready to share this information with you. Write in the comments.

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