Bobistheoilguy website

[autobackup]

This site is quite interesting for rainy day reading!

https://bobistheoilguy.com/motor-oil-101/

Quote (not mine!)!

"..............There are only two types of oil, mineral & synthetic.

If you add a different brand of mineral oil to the existing mineral oil in your sump, you will just get more mineral oil.

If you add a different brand of synthetic oil to the existing synthetic oil in your sump, you will just have more synthetic oil.

Semi-synthetic is just a blend of mineral oil & synthetic oil.

So yes you guessed it, you can add mineral to the synthetic in your sump and vice versa, you are just making your own semi-synthetic.

All engine oils mix, synthetics with minerals, one brand with another, & one weight/grade with another too.

The only things you may change is the ratio of additives, the weight/grade, & percentage of synthetic to mineral or vice versa.

Just make sure you keep the weight/grade and additive package right and you wont have any problems mixing any engine oils whatsoever......."