diff --git a/src/tile.js b/src/tile.js
index b41aa9e9..45f2823b 100644
--- a/src/tile.js
+++ b/src/tile.js
@@ -129,7 +129,7 @@ $.Tile = function(level, x, y, bounds, exists, url, context2D, loadWithAjax, aja
     this.ajaxHeaders = ajaxHeaders;
 
     if (cacheKey === undefined) {
-        $.console.error("Tile constructor needs 'cacheKey' variable: creation tile cache" +
+        $.console.warn("Tile constructor needs 'cacheKey' variable: creation tile cache" +
             " in Tile class is deprecated. TileSource.prototype.getTileHashKey will be used.");
         cacheKey = $.TileSource.prototype.getTileHashKey(level, x, y, url, ajaxHeaders, postData);
     }
diff --git a/src/viewer.js b/src/viewer.js
index df553e4c..007f1bf1 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1398,6 +1398,11 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
             options.ajaxHeaders = $.extend({}, this.ajaxHeaders, options.ajaxHeaders);
         }
 
+        if (!$.isFunction(options.tileSource.getTileHashKey)) {
+            //silently add custom implementation
+            options.tileSource.getTileHashKey = $.TileSource.prototype.getTileHashKey;
+        }
+
         var myQueueItem = {
             options: options
         };