318 low oil pressure

I agree with @Bighead440 only thing I would add is BE CAREFUL with zinc additives. Often what you will find is, the container says ZINC on it in big letters on the front, but when you flip it over it will say something like "contains no zinc" or some such. Just make SURE what you are buying has zinc in it. STP oil treatment is another good zinc additive. But DON'T get the store brand in the same size and color bottle. It contains no zinc. The Rislone that BigHead440 pointed out is a good one.