diff --git a/tools/run_tests/helper_scripts/pre_build_node.bat b/tools/run_tests/helper_scripts/pre_build_node.bat
index addb01a2a4d..62b883de466 100644
--- a/tools/run_tests/helper_scripts/pre_build_node.bat
+++ b/tools/run_tests/helper_scripts/pre_build_node.bat
@@ -29,5 +29,7 @@
 
 set PATH=%PATH%;C:\Program Files\nodejs\;%APPDATA%\npm
 
-@rem Expire cache after 1 day
-call npm update --cache-min 86400
+@rem Update npm to at least version 5
+call npm update -g npm
+
+call npm update --prefer-online
diff --git a/tools/run_tests/helper_scripts/pre_build_node.sh b/tools/run_tests/helper_scripts/pre_build_node.sh
index 083cb2bc771..b7c6e14e743 100755
--- a/tools/run_tests/helper_scripts/pre_build_node.sh
+++ b/tools/run_tests/helper_scripts/pre_build_node.sh
@@ -35,10 +35,12 @@ source ~/.nvm/nvm.sh
 nvm install $NODE_VERSION
 set -ex
 
+# Update npm to at least version 5
+npm update -g npm
+
 export GRPC_CONFIG=${CONFIG:-opt}
 
-# Expire cache after 1 day
-npm update --cache-min 86400
+npm update --prefer-online
 
 npm install node-gyp-install
 ./node_modules/.bin/node-gyp-install