Mixing Engine Oils

We all know that an engine simply cannot work without oil. It is of prime importance in lubricating moving parts in order to reduce friction and with that in mind prolong its life. There are different types of engine oils – mineral/regular oil, semi-synthetic oil and pure synthetic oil and each has its advantages and disadvantages. Each one performs differently under varied conditions. Is mixing synthetic and regular oil to get better performance at a lower price a good idea? Oils are also made available with different grade ratings that determine the viscosity and its ability to perform under varying weather conditions. Can oils of different grades be mixed? 

The good news is that mixing different types of oil it will not harm your engine in any way in the short run. Most synthetic and semi-synthetic engine oils are based on regular oil and are compatible. No unwanted by-products are created when different types of oil are mixed, and engine performance will be absolutely fine. Gone are the days when switching between synthetic and mineral oil was not recommended as people experienced problems like seal leaking and unusually high oil consumption. In fact, in places when the car is put through extreme conditions where temperature fluctuations can be especially extreme, owners switch from mineral oil to synthetic for the colder months and vice-versa. 

The bad news though is that this will not give you the benefits you think it would. Mixing different oils will not improve the performance or efficiency of the engine in any way. The additives in synthetic oil may have limited or no effect at all when mixed with a regular engine oil. Mixing different synthetic oil blends, on the other hand, may have negative effects in the long term as the additives may react. 

Now, as far as different grades are concerned, mixing between them isn’t something that will damage your engine either. Oils are miscible. You don’t need to worry about adding one to the other in any proportion as they will easily form a solution. You can use 1 litre of 5W30 mixed with 5W40 and it will not cause any sort of ill effects to the engine. Having said that, it is always better to stick to one grade of oil till the time you decide to completely drain your car and top it up. It is only recommended to top up your car with oils of different grades when you are running low in the middle of nowhere or the oil that you first used is no longer available in the market. 

Further, it is advisable not to mix two different brands of oils as their additives may or may not be compatible. Check your car manual for specific details about what kind of oil will be ideal for your car. Summing it up, when you top up your engine oil after a leak, do not hesitate to mix oils if you do not get the same type of oil. In the long run, though, stick to using one type of oil to get the best performance out of your engine.