I had to much motor oil exactly 2 1/2 quarts over I changed the oil and spark

My van was reading that it had none 's a cop put a quart in after that it worked fine then the next day did the same thing and when checked by mechanic it had nine quarts in it my van only takes five so they emptied out the oil put new and only five changed the spark plugs and it still won't stay on it starts but won't stay on IDK wat else could be the problem