diff --git a/heat/engine/resource.py b/heat/engine/resource.py
index ceaf5a72a3..621f562d2e 100644
--- a/heat/engine/resource.py
+++ b/heat/engine/resource.py
@@ -13,7 +13,6 @@
 
 import collections
 import contextlib
-import datetime as dt
 import itertools
 import pydoc
 import re
@@ -24,6 +23,7 @@ from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import excutils
 from oslo_utils import reflection
+from oslo_utils import timeutils as oslo_timeutils
 
 from heat.common import exception
 from heat.common.i18n import _
@@ -58,8 +58,6 @@ cfg.CONF.import_opt('error_wait_time', 'heat.common.config')
 
 LOG = logging.getLogger(__name__)
 
-datetime = dt.datetime
-
 
 def _register_class(resource_type, resource_class):
     resources.global_env().register_class(resource_type, resource_class)
@@ -1675,7 +1673,7 @@ class Resource(status.ResourceStatus):
 
         LOG.info('updating %s', self)
 
-        self.updated_time = datetime.utcnow()
+        self.updated_time = oslo_timeutils.utcnow()
 
         if new_requires is not None:
             self.requires = self.requires | new_requires
diff --git a/heat/tests/aws/test_waitcondition.py b/heat/tests/aws/test_waitcondition.py
index 0e31cf172f..faabaa9ed5 100644
--- a/heat/tests/aws/test_waitcondition.py
+++ b/heat/tests/aws/test_waitcondition.py
@@ -604,7 +604,7 @@ class WaitConditionUpdateTest(common.HeatTestCase):
 
         now = timeutils.utcnow()
         fake_clock = [now + datetime.timedelta(0, t)
-                      for t in (0, 0.001, 0.1, 4.1, 5.1)]
+                      for t in (0, 0, 0.001, 0.1, 4.1, 5.1, 5.1)]
         timeutils.set_time_override(fake_clock)
         self.addCleanup(timeutils.clear_time_override)
 
diff --git a/heat/tests/test_resource.py b/heat/tests/test_resource.py
index d4e893971e..a73cc4c58b 100644
--- a/heat/tests/test_resource.py
+++ b/heat/tests/test_resource.py
@@ -12,7 +12,6 @@
 #    under the License.
 
 import collections
-import datetime
 import itertools
 import json
 import os
@@ -22,6 +21,7 @@ import uuid
 
 import eventlet
 from oslo_config import cfg
+from oslo_utils import timeutils as oslo_timeutils
 
 from heat.common import exception
 from heat.common.i18n import _
@@ -600,7 +600,7 @@ class ResourceTest(common.HeatTestCase):
         res = generic_rsrc.GenericResource('test_resource', tmpl, self.stack)
         res.store()
         self.assertIsNone(res.updated_time)
-        res.updated_time = datetime.datetime.utcnow()
+        res.updated_time = oslo_timeutils.utcnow()
         res.store()
         self.assertIsNotNone(res.updated_time)