Liqui Moly MOS2 Leichtlauf is a synthetic blend oil while Liquid Moly Molygen New Generation is completely synthetic oil, both of them are used for gasoline as well as in diesel engines. MOS2 is more focused on protecting the engine against tear and wear, meanwhile, Molygen pays more attention to fuel economy.
Liqui Moly MOS2 provides excellent resistance against the engine’s wearing due to its greater anti-wear additives concentration. This oil provides decent cleaning of sludge and other contaminations. It provides compatible performance when temperature is high. Due to the addition of superior quality viscosity modifiers, it undergoes fewer viscosity variations at higher temperatures.
On the other side, the Liqui Moly Molygen provides more efficient catalytic converter performance due to its lower ZDDP compounds concentration. The presence of detergents in abundance allows superior cleaning against engine deposits. It provides high protection against its quick and early burn-off. The higher kinematic viscosities of oil at both normal and elevated temperatures allow it to provide commendable performance in different conditions. Its TBN is on the high side allowing it to work for long time.
Table of Contents
Side By Side Comparison
| Specifications | Liqui Moly MOS2 Leichtlauf (10W-40) | Liquid Moly Molygen New Generation (10W-40) |
| Oil Type | Synthetic Blend | Synthetic |
| Engine | Gasoline/ Diesel | Diesel/ Gasoline |
| Available viscosity grades | 10W-30, 10W-40, 15W-50 | 5W-40, 5W-30, 10W-40, 15W-40, 0W-20 |
| API | SL/ CF | SL |
| Interval of oil exchange (km) | 7,000 | 12,000 |
| Additives | Detergents, Anti-wears, Viscosity modifiers, Dispersants | Friction reducing agents, Viscosity modifiers, Detergents, Dispersants, Wear-resistant compounds |
| ACEA | A3/B4 | A3/B4 |
Comparing shielding against quick oil burn-off
The volatility of oil is dependent on the presence of lighter particles concentrations. The oil volatility rises if it has more lightweight molecules. This causes the oil to reach its ignition point (flashpoint) sooner than expected, causing burn off at a low temperature.
MOS2 is more volatile because of its higher quantities of light-weight particles making the oil reach its flashpoint at a relatively lower temperature.
Molygen has a comparatively higher flashpoint temperature, decreasing its volatility. This puts it ahead of its competitor with regard to quick oil burn-off protection.
| Oils in Comparison (Oils Grade 10W-40) | Flashpoint (Degrees Celsius) |
| Liqui Moly MOS2 Leichtlauf | 230 |
| Molygen New Generation | 232 |
Comparing shielding against Engine Wearing
The sliding of moving parts of an engine generates friction leading to wear and tear. Special additives called wearing-resistant agents are put into motor oil to minimize this problem. The purpose of their addition is to develop thin-film around these moving parts. This film reduces friction by lowering the interaction between moving parts. The larger amount of these additives provides greater resistance against engine wearing.
MOS2 has high concentrations of anti-wear additives providing more tough layers around the metal components. This causes lower degradation of engine by providing better protection against its wearing.
Molygen due to lower amounts of these anti-wearing agents, allows less protection to wear and tear in comparison to the other oil.
Comparing Viscosity
Hampering in the flow of a fluid is kinematic viscosity. A greater viscosity allows more commendable performances upon temperature elevations. Viscosity index is the capability of oil to resist change in its viscosity when there is an increase in temperature. Higher viscosity index ensures lower variation in the oil’s viscosity at exaggerated temperatures. Pour point decides the functioning of oil in chilly regions, which is actually a minimum temperature below which fluid can’t flow. Pour point should be low for oil to perform diligently at lower temperatures.
The performance of Molygen as compared to its rival, at a normal and higher temperature that is at 40 o C as well as 100 o C, is better because of its higher kinematic viscosity. During colder environments, it still dominates by providing better startups during such conditions due to its lower pour point temperature.
MOS2, however, has a higher viscosity index that enables it to undergo fewer variations in its kinematic viscosities, relative to that of its peer upon a surge in temperature from 40o C to 100 o C.
| Contrasting oils (Grade oils 10W-40) | Kinematic Viscosity (40 o C) (mm2/s) | Kinematic Viscosity (100 o C) (mm2/s) | Index of Viscosity (VI) | Pour point |
| Liqui Moly MOS2 Leichtlauf | 88 | 14 | 164 | -36 o C |
| Liquid Moly Molygen New Generation | 96.3 | 14.8 | 161 | -39 o C |
Effect On Catalytic converter
The oxidized oil comes in contact with the anti-wearing additives usually ZDDP and forms toxic ash. The poisonous ash enters the catalytic converter causing it to choke. This causes blockage in the working of a converter, decreasing its efficiency.
From testing, it was revealed that MOS2 contains greater quantities of these ZDDP additives making it less effective for proper catalytic converter functioning.
The performance of Molygen in comparison to its rival is better because of its lower concentrations of both zinc and phosphorus compounds. Lower concentrations produce less ash, enabling the catalytic converter to perform more effectively.
Oil Sludge Formation Comparison
A dark thick fluid called sludge is formed as a result of reaction between oxidized oil with impurities like dirt and moisture. This sludge proves to be a hurdle in the proper movement of oil inside the engine. Detergents in addition to some dispersants are being included in it to lower this issue, making the engine clean.
MOS2 due to its enormous detergent concentrations, provides higher cleaning of deposits making it superior to its peer. The higher quantities of detergents provide smoother oil flow inside the engine.
The amounts of detergent in Molygen are comparatively on the lower side, putting it behind its rival in terms of sludge reduction.
Comparison of oil changing frequency
The frequency of changing the oil depends upon a number of reasons like early oil burn-off and the number of added bases. TBN is used to estimate the concentrations of these bases. The addition of bases is done to neutralize the acids produced during the burning of motor oil. The bases concentrations decrease over time so the oil with a higher TBN provides longer oil interchanging intervals
MOS2 because of its lower TBN provides shorter oil-replacing durations. The oil is required to be changed after an interval of around 7,000 Km, less than that of its peer.
Molygen has a comparatively higher concentration of base additives which results in its higher TBN. The oil provides a longer duration of replacement after covering an average distance of around 12,000 Km.
| Oils in Comparison (10W-40 Grade oils) | TBN (mg KOH/gram) |
| Liqui Moly MOS2 Leichtlauf | 9 |
| Liquid Moly Molygen New Generation | 11 |
Quick Summary
- MOS2 is a synthetic blend oil while Molygen is fully synthetic, utilized in gasoline along with diesel engines.
- Molygen due to its lower concentrations of zinc and phosphorus is more effective in the proper functioning of the catalytic converter.
- Relatively higher amounts of detergents in Molygen allow superior sludge rinsing.
- MOS2 is more volatile due to its lower ignition point temperature.
- The quantities of anti-wear agents are higher in MOS2 resulting in more protection against engine degradation.
- Molygen performance at both higher and lower temperatures is superior to its rival.
- The higher viscosity index of MOS2 allows the oil to undergo fewer viscosity variations.
- Molygen has a higher TBN allowing a lower frequency of oil exchange.
- MOS2 is faintly higher-priced compared to that of its competitor