Can Engine Synthetic Oil Be Switched to Regular Oil? .

Question: Can Synthetic Oil Be Switched to Regular Oil? Spectro Performance Oils is answering your question.

Answer: Yes, synthetic oil can be switched to regular oil in an engine. And vice versa: the oil type can be switched as often as desired. Both synthetic and regular oils lubricate engines internally, providing a barrier that prevents metal-on-metal contact inside the engine. When synthetic oil started gaining popularity, it was thought that it would harm your engine to switch between it and regular oil. It is now believed that not only is switching harmless, but also in some circumstances it may be advantageous. Some synthetic oils are synthetic blends, which include regular oil mixed with synthetic. As these semi-synthetic oils are a blend of the two types, riders should experience no issues from switching between oil types. It has been stated that when synthetic oils were first introduced, switching from synthetic to regular oil caused leaking, mostly as a result of different seal-swell rates of the oils. However, these issues have since rectified, and there are currently no problems due to switching back and forth.

11 Responses to “Can Engine Synthetic Oil Be Switched to Regular Oil? .”


  1. 1 Ray Oct 11th, 2012 at 10:30 am

    Glad to read this because I heard many times from fellow bikers that you could not switch.

  2. 2 viz Oct 11th, 2012 at 2:10 pm

    Uh oh, not this again

  3. 3 stefan Oct 11th, 2012 at 5:00 pm

    Damn it!!! I just gave a case of Spectro regular oil because I didn’t think I could switch…

  4. 4 Rogue Oct 12th, 2012 at 8:18 am

    I have been using Spectro Golden 20w50 Semi Synthetic Oil in my 2004 FLHT after switching from Harley SYN 3 and use in my 2009 FLHTC since the first oil change.
    I am very happy with Spectro and change it and the filter every 5000 miles. Because I travel a lot I know I can count on it. An example is my trip to Sturgis this year was 5886.9 miles. Spectro went the extra miles and I never had any doubt that it was still doing its job.

  5. 5 brymob Oct 12th, 2012 at 12:08 pm

    I use Shell Rotella full synthetic 5/40 w great oil for bikes,cars,and available in many places,not bad pricing either..

  6. 6 Blackmax Oct 15th, 2012 at 5:40 pm

    I have been going back & forth
    Use the Rotella for normal everyday driving / riding which it’s fine for….
    But, if I’m going on a extended, long distance road trip, (Sturgis, Canada, etc …)
    I drain and use Spectro full synthetic

  7. 7 Blackmax Oct 15th, 2012 at 5:40 pm

    it’s just peace of mind

  8. 8 aaron Oct 16th, 2012 at 1:43 am

    I always thought the issue was that the superior lubricating qualities of a synthetic allowed a clutch to slip in a unit construction engine (shared lubrication between engine and transmission). if that’s the case, sportster/buell riders should continue to steer clear.

  9. 9 aaron Oct 16th, 2012 at 1:45 am

    and, of course just about every other bike other than the big twin. I guess some bmw boxers and older ducatis running dry clutches can pull it off too…

  10. 10 Mark Mederski Oct 22nd, 2012 at 10:26 am

    I tried switching from regular 10-40 to Mobil 1 in a car with about 100,000 miles on it and it leaked like a sieve (from many places!) for the next 100,000 miles. But that is just one car. Spectro’s a good company so there is probably some truth to what they are saying.

  11. 11 Axle Nov 3rd, 2012 at 1:11 pm

    “Yes, synthetic oil can be switched to regular oil in an engine.”
    Must be an awfully advanced engine to be able to change the molecular structure of the motor oil circulationg through it.

Comments are currently closed.
Cyril Huze