diff --git a/oslo_vmware/pbm.py b/oslo_vmware/pbm.py
index df5b33f8..007d81f4 100644
--- a/oslo_vmware/pbm.py
+++ b/oslo_vmware/pbm.py
@@ -25,7 +25,6 @@ import os
 
 import six.moves.urllib.parse as urlparse
 import six.moves.urllib.request as urllib
-import suds.sax.element as element
 
 from oslo_vmware._i18n import _LW
 from oslo_vmware import service
@@ -70,8 +69,7 @@ class Pbm(service.Service):
 
         :param cookie: cookie to set
         """
-        elem = element.Element('vcSessionCookie').setText(cookie)
-        self.client.set_options(soapheaders=elem)
+        self._vc_session_cookie = cookie
 
     def retrieve_service_content(self):
         ref = vim_util.get_moref(service.SERVICE_INSTANCE, SERVICE_TYPE)
diff --git a/oslo_vmware/service.py b/oslo_vmware/service.py
index 0a67cad2..b242ccb5 100644
--- a/oslo_vmware/service.py
+++ b/oslo_vmware/service.py
@@ -213,6 +213,7 @@ class Service(object):
                                     plugins=[ServiceMessagePlugin()],
                                     cache=_CACHE)
         self._service_content = None
+        self._vc_session_cookie = None
 
     @staticmethod
     def build_base_url(protocol, host, port):
@@ -264,16 +265,24 @@ class Service(object):
                                                fault_string,
                                                details=details)
 
-    def _add_operation_id(self, op_id):
-        """Add operation ID for the next remote call to vCenter.
+    def _set_soap_headers(self, op_id):
+        """Set SOAP headers for the next remote call to vCenter.
 
+        SOAP headers may include operation ID and vcSessionCookie.
         The operation ID is a random string which allows to correlate log
         messages across different systems (OpenStack, vCenter, ESX).
+        vcSessionCookie is needed when making PBM calls.
         """
-        headers = [element.Element('operationID').setText(op_id)]
-        if self.client.options.soapheaders is not None:
-            headers.append(self.client.options.soapheaders)
-        self.client.set_options(soapheaders=headers)
+        headers = []
+        if self._vc_session_cookie:
+            elem = element.Element('vcSessionCookie').setText(
+                self._vc_session_cookie)
+            headers.append(elem)
+        if op_id:
+            elem = element.Element('operationID').setText(op_id)
+            headers.append(elem)
+        if headers:
+            self.client.set_options(soapheaders=headers)
 
     @property
     def service_content(self):
@@ -314,6 +323,7 @@ class Service(object):
                     return
 
                 skip_op_id = kwargs.pop('skip_op_id', False)
+                op_id = None
                 if not skip_op_id:
                     # Generate opID. It will appear in vCenter and ESX logs for
                     # this particular remote call.
@@ -323,7 +333,7 @@ class Service(object):
                               managed_object._type,
                               attr_name,
                               op_id)
-                    self._add_operation_id(op_id)
+                self._set_soap_headers(op_id)
                 request = getattr(self.client.service, attr_name)
                 response = request(managed_object, **kwargs)
                 if (attr_name.lower() == 'retrievepropertiesex'):
diff --git a/oslo_vmware/tests/test_service.py b/oslo_vmware/tests/test_service.py
index 1accb92f..27168bff 100644
--- a/oslo_vmware/tests/test_service.py
+++ b/oslo_vmware/tests/test_service.py
@@ -374,7 +374,7 @@ class ServiceTest(base.TestCase):
         svc_obj.client.options.transport.cookiejar = [cookie]
         self.assertIsNone(svc_obj.get_http_cookie())
 
-    def test_add_operation_id(self):
+    def test_set_soap_headers(self):
         def fake_set_options(*args, **kwargs):
             headers = kwargs['soapheaders']
             self.assertEqual(1, len(headers))
@@ -384,20 +384,19 @@ class ServiceTest(base.TestCase):
         svc_obj = service.Service()
         svc_obj.client.options.soapheaders = None
         setattr(svc_obj.client, 'set_options', fake_set_options)
-        svc_obj._add_operation_id('fira-12345')
+        svc_obj._set_soap_headers('fira-12345')
 
-    def test_add_operation_id_with_existing_header(self):
+    def test_soap_headers_pbm(self):
         def fake_set_options(*args, **kwargs):
             headers = kwargs['soapheaders']
             self.assertEqual(2, len(headers))
-            txt = headers[0].getText()
-            self.assertEqual('fira-12345', txt)
-            self.assertEqual('vc-session-cookie', headers[1])
+            self.assertEqual('vc-session-cookie', headers[0].getText())
+            self.assertEqual('fira-12345', headers[1].getText())
 
         svc_obj = service.Service()
-        svc_obj.client.options.soapheaders = 'vc-session-cookie'
+        svc_obj._vc_session_cookie = 'vc-session-cookie'
         setattr(svc_obj.client, 'set_options', fake_set_options)
-        svc_obj._add_operation_id('fira-12345')
+        svc_obj._set_soap_headers('fira-12345')
 
 
 class MemoryCacheTest(base.TestCase):