Is it safe?

Is it safe to switch back and forth between conventional oil and synthetic. I change my oil every 6 months and thinking of switching to synthetic.

Sure you can. You can switch back and forth all you want. Afterall, they make synthetic blended oils. Part synthetic oil, part regular oil.


Is it safe? Hmm, I admit I dont know, but my old dad told me that you should not mix these oils, say add a quart of one to a crankcase filled with the other. If it was me, I would look for a way to flush the old oil before I added a new type. While it is true you can get multi blend oils, these are formulated oils, not random mixes. But what do I know, I am just a shade tree guy not an expert.

It is safe if your car’s manufacturer has not specified the use of synthetic.

You change your oil every 6 months… How many miles is that? Why do you want to change back and forth?

That’s what the schedule calls for 6 months or 5K miles whichever comes first. Because I was thinking of just going synthetic in summer time.

Absolutely safe. you can change back and forth as much as you want with no problems.

It is completely, absolutely, and totally safe. The two are totally compatible. They are chemically the same except that synthetic is a bit more pure and has more consistant molecular size…allegedly. has a good primer on oils. I recommend a visit.

I would be more likely to use the synthetic in the WINTER, unless you live in the South. The great value of synthetic is its extremely low pour point, like -45F, and that it provides full lubrication very quickly on cold mornings.

Many companies in the North (Alaska, etc) have standardized on Mobil 1.

Good point. I may just do that.

Yes. Change with what you please as long as it meets spec. For a matrix any modern bottle will.