diff --git a/streamz/core.py b/streamz/core.py
index 02d77dfc..ae7a27f9 100644
--- a/streamz/core.py
+++ b/streamz/core.py
@@ -51,7 +51,7 @@ def get_io_loop(asynchronous=None):
             return client.loop
 
     if not _io_loops:
-        loop = IOLoop()
+        loop = IOLoop(make_current=False)
         thread = threading.Thread(target=loop.start)
         thread.daemon = True
         thread.start()
diff --git a/streamz/tests/test_core.py b/streamz/tests/test_core.py
index b1c51280..96ab9a24 100644
--- a/streamz/tests/test_core.py
+++ b/streamz/tests/test_core.py
@@ -444,7 +444,8 @@ def test_timed_window_metadata():
     ]
 
 
-def test_timed_window_timedelta(clean):  # noqa: F811
+@pytest.mark.asyncio
+async def test_timed_window_timedelta(clean):  # noqa: F811
     pytest.importorskip('pandas')
     source = Stream(asynchronous=True)
     a = source.timed_window('10ms')
diff --git a/streamz/utils_test.py b/streamz/utils_test.py
index 9dbc1749..6ff76ad7 100644
--- a/streamz/utils_test.py
+++ b/streamz/utils_test.py
@@ -43,16 +43,11 @@ def double(x):
 
 @contextmanager
 def pristine_loop():
-    IOLoop.clear_instance()
-    IOLoop.clear_current()
-    loop = IOLoop()
-    loop.make_current()
+    loop = IOLoop(make_current=False)
     try:
         yield loop
     finally:
         loop.close(all_fds=True)
-        IOLoop.clear_instance()
-        IOLoop.clear_current()
 
 
 def gen_test(timeout=10):