Once you have switched to synthetic oil, you can’t go back. Synthetic oil is significantly slipperier than conventional oil by nature, which means that in a conventional engine it can cause leaks (which are dangerous and expensive). This is because the additives used to create synthetic oil make it more slippery than conventional oil, which could cause leaks in older cars. Synthetic oils are also engineered to resist breakdown better than conventional oils—meaning that even if you have an older car, once you switch to synthetic, you will never be able to switch back. You’ll also want to consider your driving habits when making the decision about whether or not to use synthetic oil. If you do a lot of stop-and-go driving or city driving in general (which creates a lot of heat from friction), then synthetic would likely be best for your car; if most of your driving happens on the highway and involves long trips, then conventional might be sufficient for your needs.
Mixing synthetic and conventional oil is not recommended by manufacturers.
For one thing, the manufacturers of your car and engine oils don’t recommend mixing synthetic and conventional oil. The reason for this is that synthetic oils are engineered to perform better, provide longer-lasting protection, and be more resistant than conventional oils. However, this doesn’t mean they’re necessarily better for your car. In fact, if you have an older car with a high mileage—one where the seals may have already leaked and lost their original elasticity—you can actually use a partially-synthetic or even full synthetic oil to help restore some of that elasticity to the seals in your engine.
If you decide not to mix synthetic and conventional oil, it’s important to consider how draining all the old oil from your vehicle will affect your long-term expenses. For example, conventional motor oils are less expensive than synthetic ones; plus, you’ll need to dispose of what remains in your existing oil pan instead of being able to reuse it later on.
Synthetic oil is engineered to perform better, but that doesn’t mean it’s better for your car.
While synthetic oil is engineered to perform better than conventional oils, it doesn’t always mean it’s a better choice for your car. There are several reasons why switching from synthetic to conventional oil may be a good idea:
- Synthetic oils are designed to withstand higher levels of heat and prevent deposits from forming in your engine. However, if the average temperature in your area is below 70 degrees F or there isn’t much stop-and-go driving in your daily routine, you can likely get away with using conventional motor oil. You’ll still need to change it out every 3,000 miles or less, but it should do just fine for keeping your engine running smoothly.
- Cost can also factor into which type of oil you use in your car. If money is tight, you can save by going with a conventional motor oil. It’s not as good at reducing emissions and increasing fuel efficiency as its synthetic counterpart, but if you’re looking for an option that will simply keep everything running without breaking the bank, this is it!
A switch to synthetic oils could actually hurt your car.
Switching from conventional to synthetic oil is a little like eating your vegetables and then finding out that you can’t eat ice cream for dessert because it’s too rich. You might think about just going back to regular oil after synthetic, but the two oils don’t mix well. Conventional oil could dilute the performance of synthetic oil, and vice versa.
If you do switch back to conventional oil, you’ll need to change your oil more often than if you were using only conventional engine oils in the first place.
Synthetic and conventional oils should not be mixed.
We used to think that when it came to changing your oil, there was no harm in mixing conventional and synthetic. We thought that after the initial switch, you could use whichever type of oil you wanted on your next fill-up. After all, we reasoned, how different can these oils really be?
As it turns out, they’re very different. In fact, mixing synthetic and conventional oils will cause an imbalance in the properties of the two oils that affect the way they react with one another when heated. This will result in a breakdown of the mixture—meaning the oil will perform poorly in your car and won’t protect your engine.
Therefore: if you’ve switched from conventional to synthetic, only use synthetic from here on out! And vice versa—if you’ve been using synthetic for a long time but have now decided to go with conventional instead, there’s no need to flush out all traces of old oil before filling up with new conventional oil.