Skip the auto shop - Our mechanics make house calls

Q: I had an oil change and Castrol GTX was used, which I assume is not a synthetic oil. Will that harm my engine.

asked by on

will regular engine oil used for an oil change harm the Subaru 2013 legacy 2.5 which has before this always had synthetic oil

My car has 25000 miles.
My car has an automatic transmission.

Synthetic vs conventional oil is one of the most debated myths surrounding the topic of oil changes. This will not hurt your engine when switching from synthetic to conventional or vice versa. In fact, Synthetic blend oils are actually a mix of conventional oils and synthetic oils. It is recommended that you use the same oil to top off when needed, giving you the best protection from the oil you have chosen to use in your vehicle. Many people often wonder about the benefits of using synthetic oils.

Many synthetic oils are made up of a base oil of approximately 80%, with other additives making up the remaining 20%. The main difference between the molecules in synthetically engineered oils are the uniformity of the molecules, while the molecules found in most conventional oils differ in shape, size and impurity. The type of oil that should be used for a specific application depends largely on the driver’s driving habits, the environment in which the car is driven, the mileage on the car’s engine and the limits that the engine may be pushed to. I would recommend having an expert from YourMechanic come to your home to perform an oil change service on your car to determine the best option for your vehicle in the future.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  • Home
  • Questions
  • I had an oil change and Castrol GTX was used, which I assume is not a synthetic oil. Will that harm my engine.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Check Engine Light on after changing oil - 2012 Kia Rio5

If starting it today was the first time after changing your oil, the oil filter and oil galleries were empty for a few seconds. If this is the case, the Check Engine Light is reflecting the lack of oil pressure...

Q: Various maintenance lights on.

It is possible that the high humidity in your vehicle may be causing a short within the computer. Allow the vehicle to completely dry out and go from there. Hopefully it will get better. Go get some Damp Rid and...

Q: Jdm bg5 ej20 twin turbo boost issues

Oil in the intercooler is generally a sign that a turbo seal has let go. Most likely one or both turbos are due for replacement or rebuild. Have a professional come look into the Check Engine Light code and smoke...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.