diff --git a/lib/oauth2.js b/lib/oauth2.js
index c7c8982..00c04c5 100644
--- a/lib/oauth2.js
+++ b/lib/oauth2.js
@@ -103,8 +103,7 @@ exports.OAuth2.prototype._request= function(method, url, headers, post_body, acc
   }
 
   if( access_token && !('Authorization' in realHeaders)) {
-    if( ! parsedUrl.query ) parsedUrl.query= {};
-    parsedUrl.query[this._accessTokenName]= access_token;
+    realHeaders.Authorization = this.buildAuthHeader(access_token);
   }
 
   var queryStr= querystring.stringify(parsedUrl.query);