diff --git a/pandas/tests/io/parser/test_parse_dates.py b/pandas/tests/io/parser/test_parse_dates.py
index c0b29d5019675..a73768e9ccca7 100644
--- a/pandas/tests/io/parser/test_parse_dates.py
+++ b/pandas/tests/io/parser/test_parse_dates.py
@@ -56,6 +56,40 @@ def test_separator_date_conflict(all_parsers):
     tm.assert_frame_equal(df, expected)
 
 
+def test_read_csv_with_custom_date_parser(all_parsers):
+    # GH36111
+    def __custom_date_parser(time):
+        time = time.astype(np.float)
+        time = time.astype(np.int)  # convert float seconds to int type
+        return pd.to_timedelta(time, unit="s")
+
+    testdata = StringIO(
+        """time e n h
+        41047.00 -98573.7297 871458.0640 389.0089
+        41048.00 -98573.7299 871458.0640 389.0089
+        41049.00 -98573.7300 871458.0642 389.0088
+        41050.00 -98573.7299 871458.0643 389.0088
+        41051.00 -98573.7302 871458.0640 389.0086
+        """
+    )
+    result = all_parsers.read_csv(
+        testdata,
+        delim_whitespace=True,
+        parse_dates=True,
+        date_parser=__custom_date_parser,
+        index_col="time",
+    )
+    expected = pd.DataFrame(
+        {
+            "e": [-98573.7297, -98573.7299, -98573.7300, -98573.7299, -98573.7302],
+            "n": [871458.0640, 871458.0640, 871458.0642, 871458.0643, 871458.0640],
+            "h": [389.0089, 389.0089, 389.0088, 389.0088, 389.0086],
+        },
+        index=[41047, 41048, 41049, 41050, 41051],
+    )
+    tm.assert_frame_equal(result, expected)
+
+
 @pytest.mark.parametrize("keep_date_col", [True, False])
 def test_multiple_date_col_custom(all_parsers, keep_date_col):
     data = """\
diff --git a/pandas/tests/series/test_dtypes.py b/pandas/tests/series/test_dtypes.py
index d59f0c05c7462..ac9ac6c040d6d 100644
--- a/pandas/tests/series/test_dtypes.py
+++ b/pandas/tests/series/test_dtypes.py
@@ -111,4 +111,17 @@ def test_reindex_astype_order_consistency(self):
         new_dtype = str
         s1 = s.reindex(new_index).astype(temp_dtype).astype(new_dtype)
         s2 = s.astype(temp_dtype).reindex(new_index).astype(new_dtype)
-        tm.assert_series_equal(s1, s2)
+        tm.assert_series_equal(s1, s2
+        
+    def test_series_with_object_dtype(self):
+        # GH 21881
+        timestamp = pd.Timestamp(1412526600000000000)
+        series = pd.Series([], dtype=object)
+        series['timestamp'] = timestamp
+        expected = type(series.timestamp)
+
+        series = pd.Series([], dtype=object)
+        series['anything'] = 300.0
+        series['timestamp'] = timestamp
+        result = type(series.timestamp)
+        assert result == expected