In a large bowl, mix together the ground beef, onion soup mix, bread crumbs, and milk using your hands. Shape into meatballs.
In a skillet, add the oil and heat to medium high.Lightly dredge the meatballs in the flour and shake off the excess flour. Add the meatballs in batches to the skillet and brown on all sides.
Add the meatballs to the slow cooker .
In a large bowl, add the cream of chicken soup, au jus mix and water. Whisk until smooth and mixed well.
Pour over the meatballs in the crockpot and cook on high 3-4 hours or low 4-5 hours.
Serve over rice or egg noodles.