Overwriting eventViewer in "eventViewer = null" leaks the resource that "eventViewer refers to in C#

Question

 for (int i = 0; i < auditList.Count; i++)
            {
                audit = (XEAudit)auditList[i];
                XEEventViewer eventViewer = audit.GetEventViewer();
                if (eventViewer != null)
                {
                    while (eventViewer.NextEvent())
                    {
                        if ((eventViewer.GetSeverity() == "Normal") || (eventViewer.GetSeverity() == "Critical"))
                            validationFailed = true;
                        break;
                    }
                    //);

                    //We assume that there is only one request per call so we will return the 
                    // first data content
                    if (validationFailed == true)
                    {
                        StandardException innerException = traverseDN(OutermostException); ;
                        OutermostException = innerException;
                    }
                }
                //To avoid Resource leak
                eventViewer = null;

            }

Above is the line of code where in I am trying to resolve the error :

Overwriting eventViewer in "eventViewer = null" leaks the resource that "eventViewer refers to.

I have tried to use eventViewer.Dispose() too after assigning it to null. But not sure why its not helping out.