diff --git a/loopback/common/models/loggable.js b/loopback/common/models/loggable.js
index 956762be2..28a6075d0 100644
--- a/loopback/common/models/loggable.js
+++ b/loopback/common/models/loggable.js
@@ -291,7 +291,8 @@ module.exports = function(Self) {
      * @param {*} properties Modified object properties
      */
     function removeUnloggable(definition, properties) {
-        const propList = Object.keys(properties);
+        const objectCopy = Object.assign({}, properties);
+        const propList = Object.keys(objectCopy);
         const propDefs = new Map();
 
         for (let property in definition.properties) {
@@ -302,10 +303,15 @@ module.exports = function(Self) {
 
         for (let property of propList) {
             const propertyDef = propDefs.get(property);
+            const firstChar = property.substring(0, 1);
+            const isPrivate = firstChar == '$';
 
-            if (!propertyDef) return;
+            if (isPrivate || !propertyDef)
+                delete properties[property];
 
-            if (propertyDef.log === false)
+            if (!propertyDef) continue;
+
+            if (propertyDef.log === false || isPrivate)
                 delete properties[property];
             else if (propertyDef.logValue === false)
                 properties[property] = null;