diff --git a/searx/engines/deviantart.py b/searx/engines/deviantart.py
index ef1dd9e5..d893fc7f 100644
--- a/searx/engines/deviantart.py
+++ b/searx/engines/deviantart.py
@@ -13,7 +13,6 @@
 """
 
 from urllib import urlencode
-from urlparse import urljoin
 from lxml import html
 import re
 from searx.engines.xpath import extract_text
@@ -39,7 +38,7 @@ def request(query, params):
 
     params['url'] = search_url.format(offset=offset,
                                       query=urlencode({'q': query}))
-    if params['time_range']:
+    if params['time_range'] in time_range_dict:
         params['url'] += time_range_url.format(range=time_range_dict[params['time_range']])
 
     return params
diff --git a/searx/engines/duckduckgo.py b/searx/engines/duckduckgo.py
index aa7a9875..2153492e 100644
--- a/searx/engines/duckduckgo.py
+++ b/searx/engines/duckduckgo.py
@@ -67,7 +67,7 @@ def request(query, params):
         params['url'] = url.format(
             query=urlencode({'q': query}), offset=offset)
 
-    if params['time_range']:
+    if params['time_range'] in time_range_dict:
         params['url'] += time_range_url.format(range=time_range_dict[params['time_range']])
 
     return params
diff --git a/searx/engines/google.py b/searx/engines/google.py
index 3b845cbc..ea93bc94 100644
--- a/searx/engines/google.py
+++ b/searx/engines/google.py
@@ -185,7 +185,7 @@ def request(query, params):
                                       query=urlencode({'q': query}),
                                       hostname=google_hostname,
                                       lang=url_lang)
-    if params['time_range']:
+    if params['time_range'] in time_range_dict:
         params['url'] += time_range_search.format(range=time_range_dict[params['time_range']])
 
     params['headers']['Accept-Language'] = language
diff --git a/searx/engines/google_images.py b/searx/engines/google_images.py
index b687317c..090d4470 100644
--- a/searx/engines/google_images.py
+++ b/searx/engines/google_images.py
@@ -11,7 +11,6 @@
 """
 
 from urllib import urlencode
-from urlparse import parse_qs
 from json import loads
 from lxml import html
 
@@ -39,7 +38,7 @@ def request(query, params):
     params['url'] = search_url.format(query=urlencode({'q': query}),
                                       offset=offset,
                                       safesearch=safesearch)
-    if params['time_range']:
+    if params['time_range'] in time_range_dict:
         params['url'] += time_range_search.format(range=time_range_dict[params['time_range']])
 
     if safesearch and params['safesearch']:
diff --git a/searx/engines/yahoo.py b/searx/engines/yahoo.py
index 82f782b9..8e24a283 100644
--- a/searx/engines/yahoo.py
+++ b/searx/engines/yahoo.py
@@ -58,7 +58,7 @@ def parse_url(url_string):
 
 
 def _get_url(query, offset, language, time_range):
-    if time_range:
+    if time_range in time_range_dict:
         return base_url + search_url_with_time.format(offset=offset,
                                                       query=urlencode({'p': query}),
                                                       lang=language,
diff --git a/tests/unit/engines/test_deviantart.py b/tests/unit/engines/test_deviantart.py
index c00bb8fa..75c59f76 100644
--- a/tests/unit/engines/test_deviantart.py
+++ b/tests/unit/engines/test_deviantart.py
@@ -10,6 +10,7 @@ class TestDeviantartEngine(SearxTestCase):
         query = 'test_query'
         dicto = defaultdict(dict)
         dicto['pageno'] = 0
+        dicto['time_range'] = ''
         params = deviantart.request(query, dicto)
         self.assertTrue('url' in params)
         self.assertTrue(query in params['url'])
diff --git a/tests/unit/engines/test_duckduckgo.py b/tests/unit/engines/test_duckduckgo.py
index 90cdc9d9..cb866d39 100644
--- a/tests/unit/engines/test_duckduckgo.py
+++ b/tests/unit/engines/test_duckduckgo.py
@@ -12,6 +12,7 @@ class TestDuckduckgoEngine(SearxTestCase):
         dicto = defaultdict(dict)
         dicto['pageno'] = 1
         dicto['language'] = 'de_CH'
+        dicto['time_range'] = ''
         params = duckduckgo.request(query, dicto)
         self.assertIn('url', params)
         self.assertIn(query, params['url'])
diff --git a/tests/unit/engines/test_google.py b/tests/unit/engines/test_google.py
index 37a83cae..8e73e2ab 100644
--- a/tests/unit/engines/test_google.py
+++ b/tests/unit/engines/test_google.py
@@ -19,6 +19,7 @@ class TestGoogleEngine(SearxTestCase):
         dicto = defaultdict(dict)
         dicto['pageno'] = 1
         dicto['language'] = 'fr_FR'
+        dicto['time_range'] = ''
         params = google.request(query, dicto)
         self.assertIn('url', params)
         self.assertIn(query, params['url'])
diff --git a/tests/unit/engines/test_google_images.py b/tests/unit/engines/test_google_images.py
index 5f184e00..1cfba60b 100644
--- a/tests/unit/engines/test_google_images.py
+++ b/tests/unit/engines/test_google_images.py
@@ -11,6 +11,7 @@ class TestGoogleImagesEngine(SearxTestCase):
         dicto = defaultdict(dict)
         dicto['pageno'] = 1
         dicto['safesearch'] = 1
+        dicto['time_range'] = ''
         params = google_images.request(query, dicto)
         self.assertIn('url', params)
         self.assertIn(query, params['url'])
diff --git a/tests/unit/engines/test_yahoo.py b/tests/unit/engines/test_yahoo.py
index 11ef9db2..1226f92a 100644
--- a/tests/unit/engines/test_yahoo.py
+++ b/tests/unit/engines/test_yahoo.py
@@ -28,6 +28,7 @@ class TestYahooEngine(SearxTestCase):
         query = 'test_query'
         dicto = defaultdict(dict)
         dicto['pageno'] = 1
+        dicto['time_range'] = ''
         dicto['language'] = 'fr_FR'
         params = yahoo.request(query, dicto)
         self.assertIn('url', params)