The answer is, well, not much.
But you don’t have to rely solely on oil manufacturers to find oil that is safe to drink.
We’ve compiled a list of more than 100 oil and chemical products and brands we’ve found that we believe to be safe for your car.
If you’re not sure which brand of engine oil is right for your vehicle, check out our list of the Top 10 Best Engine Oil Brands for 2018.
The top brands are listed alphabetically, with links to their official web sites, which also offer detailed information about each product and how to make a decision.