"v" belts sequel if they or the pulley are worn or not tensioned correctly.Spraying with WD 40 will only make it worse in the long term as it is a lubricant,and will make your belts hard and brittle.You could purchase a proper belt dressing spray which would help as a quick cure.Best advice is to have the belts removed and inspected,with an eye on renewing. Good Motoring GCJH