Roadstar

Can you switch back to conventional motor oil once you've used synthetic.Thanks

Bigiron

Yes. There should be no problem, although it is best not to mix them. But that is true with mixing brands of Dino or synthetic also.

Lost Lake

Oil is oil. All oils say they are compatible with other oils. If you have concerns contact Blackstone or another oil analysis lab and ask them if there could be any harm in mixing synthetic and dino oils.

1-2-3

To switch either way, some oil will have to be mixed. No way to avoid it. I've never heard of any issues.

Bigiron

Could be an old wives tail, but I heard long ago that it is better not to mix the addative packages of different brands of oil. I always followed the advice, but I haven't done any testing to see if it actually makes a difference.

marathon

I posted this awhile back for a similar question:

I used to do analysis of motor oils for Maryland. You can switch from dino to synthetic fine and always replace the filter too. Don't mix synth with dino or even other brands of synth or dino together. It's not the oils themselves, it's the additives. Each batch has a unique mix of additives. The additives may be so different, that they cancel each other out or worse, react and make a sludge.

Lost Lake

Can you elaborate? Which additives in our oils can react and create sludge? This is great information, and I'd like to know if any two oils added together at one time could create a reaction.

Otherwise I'd have to call this one BS

Just saying.... If there is a possible reaction I'd like to know it! I think we all would! What if we're 200 miles from anywhere and we need to add 6 quarts of oil and all we can get is brand X, and we are using brand Z. Are there any two oils that when mixed will cause a real problem?

My gut is saying no, but if my gut was always right I'd be a zillionaire!

1-2-3

Unless you totally disassemble your engine, you will never ever avoid mixing a very small amount. The point is, choose one and stick with it.

marathon

If you take a look at the attached file you'll get an idea of how complex the lube oil standards are for our trucks. Each batch of oil is different and to get a particular batch to pass all the tests, the manufacturers use additives. The problem is that very different additives can be used to get similar results.


Of course, if you're stuck somewhere, you have to take what you can get.

bigramdiesel

Yes you can mix oil's. You can even buy a synthetic oil, conventional oil blend. I know a guy that has been blending his own oils for 40 years now.
He blends 10 weight with 40 weight. He thinks it will work better than 10x40.

billie

^^ He must be awful confident that he can produce a product better than a lab and a scientific staff dedicated to the task.

IMO most of the advertising is hype. I use dino and synthetic for different applications and have never had an oil related failure ever. I have a small generator that's showing some age but at +3000hrs on a B&S engine, it's earned its RIP .