1. What is Mineral Oil?
Mineral oils are directly derived from refined crude petroleum oil. During the process, natural contaminants and unwanted hydrocarbons are removed. However, mineral oils are thicker and flow through the engine circuit slowly, resulting in increased fuel consumption.
Advantages of Mineral Oils:
• Mineral oils are ideal for older vehicle models
• Mineral oils are much lower in cost
• Lubricate moving parts in an engine and, according to the level of refinement, can perform well in varied conditions
• Are cheaper compared to semi-synthetic or synthetic oils

Disadvantages of Mineral Oils:
• The markedly simple way that they are produced compared to synthetic blends of oil makes them unstable and prone to loss of viscosity under extreme conditions.
• They contain some contaminants which form sludge. This can be dangerous in the long run if the oil change intervals are not followed
• Mineral oils require frequent oil changes

2. What is Semi Synthetic Oil?
Semi-synthetic oil is a mix of fully synthetic oil and conventional mineral oil. Although it cannot get higher levels of performance than fully synthetic oil, it performs better than the conventional mineral oil.
Advantages of Semi Synthetic Oils:
• Better Fuel Economy when compared to Mineral Oil: The low viscosity and low friction characteristics of the semi-synthetic oil offers an improved fuel economy for your vehicle.
• Better Price: Like the best of both worlds, semi-synthetic oil offers the best of fully synthetic oil like lubricant life and improved viscosity at lower prices than the fully synthetic oil.
• Better Engine Defense: This oil usually has better engine defense than other oils when it comes to higher temperatures and heavier loads.

Disadvantages of Semi Synthetic Oils:
• Limits breaking in for new vehicle's parts: New vehicles require some level of friction for their moving parts to break in. The synthetic oil limits this first baby step for brand new rides. Friction resistance of the oil brings about this effect.
• Old vehicle models are at risk too: Old vehicle models, especially from 1990 dating back, don't go well with synthetic oil. Most old models use deposits as sealing in the oil system. What the synthetic oil does is cleaning out the deposits.
• Expensive than Mineral Oil: High cost of the oil definitely has to factor in the disadvantages. Of course this is a high quality oil that has the best production work put into it. High cost of production for this product is the main reason for the cost.

3. What is Fully Synthetic Oil?
Fully synthetic oil is distilled, refined, and purified to a level which ultimately results in individual molecules in the oil to up their performance in such a way that it perfectly fits the demand of a modern automobile. It also degrades at a slower rate and hence, it will have better performance than Semi Synthetic & mineral oil.

Advantages of Fully Synthetic Oil:
• Fewer Impurities: Fully synthetic oil contains fewer impurities than mineral oil & semi synthetic oil, so it is more environment friendly and helps in controlling carbon emissions.
• Better Protection: Fully synthetic oil retains its engine protection for a longer time, particularly in extreme heat. Whereas mineral can break down and evaporate.
• Better Fluid Mobility: The oil freely circulates and reaches everywhere as soon as the engine is started. But, when it comes to the conventional oil that is used, it takes its own time to start and let the oil reach its destination.

Disadvantages of Fully Synthetic Oil:
• Expensive than mineral oil and semi synthetic oil: Their technology intensive production method renders them costlier,i.e., It is way more costlier then both mineral and semi synthetic oils.
• Not compatable with budget cars: They are not recommended on high-mileage engines, as their chemical composition has been known to affect the rubber seals and cause oil leaks and their effectiveness on low performance engines is not significant.
• Possible additive precipitation/separation: Synthetics may be more prone to additives precipitation during cold storage conditions. This stratifies certain additives which can potentially lead to their complete separation from the oil.

Conclusion:
In the end, Which oil would be best for you solely depends on the car you drive. Different Engines needs different types of oils, But as a car enthusiast i always recommend Eiffels Lubricants and Engine Oils to everyone.
Eiffel Lubricants provides the best Quality Engine Oils on the cheaper price as compared to others. Eiffel Lubricants never compromises on its quality and always give great results for long.
If you're a car enthusiast too and live in Australia i recommend you to visit Eiffel Lubricants(eiffellubricants.com.au) to understand about the engine oils more.