diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index c5b8141ff07..503e32a31e9 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -218,22 +218,34 @@ function comment_count_unpublished() {
   return t('Unapproved comments (@count)', array('@count' => $count));
 }
 
+/**
+ * Implements hook_ENTITY_TYPE_insert() for 'field_instance'.
+ */
+function comment_field_instance_insert(FieldInstanceInterface $instance) {
+  if ($instance->getType() == 'comment' && !$instance->isSyncing()) {
+    \Drupal::service('comment.manager')->addBodyField($instance->entity_type, $instance->getName());
+    \Drupal::cache()->delete('comment_entity_info');
+  }
+}
+
 /**
  * Implements hook_ENTITY_TYPE_create() for 'field_instance'.
  */
 function comment_field_instance_create(FieldInstanceInterface $instance) {
   if ($instance->getType() == 'comment' && !$instance->isSyncing()) {
-    \Drupal::service('comment.manager')->addBodyField($instance->entity_type, $instance->getName());
-    \Drupal::cache()->delete('comment_entity_info');
     // Assign default values for the field instance.
-    $instance->default_value = array(array(
+    if (!isset($instance->default_value)) {
+      $instance->default_value = array();
+    }
+    $instance->default_value += array(array());
+    $instance->default_value[0] += array(
       'status' => COMMENT_OPEN,
       'cid' => 0,
       'last_comment_timestamp' => 0,
       'last_comment_name' => '',
       'last_comment_uid' => 0,
       'comment_count' => 0,
-    ));
+    );
   }
 }
 
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentFieldsTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentFieldsTest.php
index 0e697395548..c0b2aaf9487 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentFieldsTest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentFieldsTest.php
@@ -57,6 +57,11 @@ class CommentFieldsTest extends CommentTestBase {
     $this->assertTrue($field, 'The comment_body field exists');
     $instances = $this->container->get('field.info')->getInstances('comment');
     $this->assertTrue(isset($instances['node__comment']['comment_body']), format_string('The comment_body field is present for comments on type @type', array('@type' => $type_name)));
+
+    // Test adding a field that defaults to COMMENT_CLOSED.
+    $this->container->get('comment.manager')->addDefaultField('node', 'test_node_type', 'who_likes_ponies', COMMENT_CLOSED);
+    $field = entity_load('field_instance', 'node.test_node_type.who_likes_ponies');
+    $this->assertEqual($field->default_value[0]['status'], COMMENT_CLOSED);
   }
 
   /**
diff --git a/core/modules/field/field.purge.inc b/core/modules/field/field.purge.inc
index 95af3a72f0b..cd8cd04b968 100644
--- a/core/modules/field/field.purge.inc
+++ b/core/modules/field/field.purge.inc
@@ -85,12 +85,6 @@ function field_purge_batch($batch_size) {
       continue;
     }
 
-    // EntityFieldQuery currently fails on conditions on comment bundle.
-    // Remove when http://drupal.org/node/731724 is fixed.
-    if ($entity_type == 'comment') {
-      continue;
-    }
-
     $ids = (object) array(
       'entity_type' => $entity_type,
       'bundle' => $instance->bundle,