Can High Mileage Oil Be Used In Low Mileage Cars?

To answer the question of whether high mileage oil can be used in low mileage cars, let's first define exactly what it is. A high mileage oil is made with seal conditioners and additives that minimize or eliminate leaks, both inside and outside the engine. The seals and gaskets swell, reducing oil leakage and consumption. 

High mileage engine oil can also have specific additive packages that use high detergent levels to remove deposits and sludge from your engine or minimize engine wear. This type of oil is usually is designed for engines with over 75,000 miles, but choosing the right brand of high mileage motor oil is very important. 

Moving on to whether high mileage oil can be used in low mileage cars, let's now determine whether any of the effects of high mileage oils can be bad for low mileage cars. While most sources state that high mileage oils may not provide any benefits for newer of lower-mileage engines, Autozone states that, "...the seal conditioners could lead to excess seal softening in newer vehicles, potentially causing issues." 

Another factor is cost, as high mileage oils tend to cost more than conventional oils, thanks to their special additive packages that provide additional protection for these engines. Bottom line, there's no need. 

The engines that are the best candidates for high mileage oils are those that have more than 75,000 miles on them and have been otherwise properly maintained. In addition, if your high mileage engine is also burning and/or leaking oil, the additives blended into these high mileage oils may reduce or eliminate these issues. Of course, when changing out the oil, an oil filter from a good brand is a necessity.

Keep in mind that there are also some high mileage engines that may not be good candidates for high mileage oils. These engines include those that were not properly serviced at regular intervals, and are experiencing severe problems like cylinder slap, loss of power, leakage of combustion gases from the combustion chamber into the crankcase, odd mechanical sounds, coolant or fuel mixing with the oil, and so on. These are serious issues that require the intervention of a skilled mechanic — simply pouring high mileage oil into the engine will not remedy them.

As far as using high mileage oil in low mileage cars, there is simply no point in doing it. It will cost you more than the equivalent standard motor oil and it could definitely do some harm if the seal-softening additives cause your engine to leak or burn oil.