I do not recommend that you change viscosity due to manufacturer specs. Having an oil change just 4wks ago would not prevent a leak! You may need to inspect your drain plug, valve cover gaskets, and oil pan gaskets for oil residue indicating a leak. Your change oil light may have appeared prematurely due to not resetting the light at time of service.
〉 Answered on Feb 9th, 2016 by Amanda J. Pierce, MBA "AJ", Certified Mechanic, Project Coordinator; Primavera Scheduler at VIGOR Alaska Industrial Shipyard & BizzM3ch Solutions