Wicksfield - 1/15/2018 21:01

It's very important to use the same brand.  In a quart of oil, only about half is oil.  The other half is additives.  Some manufacturers additives are not compatible with others.  If you're on the road and need oil, by all means, add it but then change it first chance.   This information from a retired Shell test engineer.  BTW, he said all name brand oil is good.