Slick 50, or any other oil treatment that does the same thing.
My old scrap hauler lost an oil pump and due to money and time constraints, I had to drive it for a couple of months like that.
After I replaced the oil pump it performed the same as it did before the oil pump went bad.
When I bought it I added a quart of slick 50 the first time I changed the oil, I think if I didn't do that I would have lost the engine.