diff --git a/cluster/gce/container-linux/configure-helper.sh b/cluster/gce/container-linux/configure-helper.sh
index f8a1f8531e1..b2aaee20d92 100755
--- a/cluster/gce/container-linux/configure-helper.sh
+++ b/cluster/gce/container-linux/configure-helper.sh
@@ -1155,7 +1155,7 @@ function start-cluster-autoscaler {
     local -r src_file="${KUBE_HOME}/kube-manifests/kubernetes/gci-trusty/cluster-autoscaler.manifest"
     remove-salt-config-comments "${src_file}"
 
-    local params="${AUTOSCALER_MIG_CONFIG} ${CLOUD_CONFIG_OPT} ${AUTOSCALER_EXPANDER_CONFIG:-}"
+    local params="${AUTOSCALER_MIG_CONFIG} ${CLOUD_CONFIG_OPT} ${AUTOSCALER_EXPANDER_CONFIG:---expander=price}"
     sed -i -e "s@{{params}}@${params}@g" "${src_file}"
     sed -i -e "s@{{cloud_config_mount}}@${CLOUD_CONFIG_MOUNT}@g" "${src_file}"
     sed -i -e "s@{{cloud_config_volume}}@${CLOUD_CONFIG_VOLUME}@g" "${src_file}"
diff --git a/cluster/gce/gci/configure-helper.sh b/cluster/gce/gci/configure-helper.sh
index e6fbfa582ee..13e3c973b91 100644
--- a/cluster/gce/gci/configure-helper.sh
+++ b/cluster/gce/gci/configure-helper.sh
@@ -1558,7 +1558,7 @@ function start-cluster-autoscaler {
     local -r src_file="${KUBE_HOME}/kube-manifests/kubernetes/gci-trusty/cluster-autoscaler.manifest"
     remove-salt-config-comments "${src_file}"
 
-    local params="${AUTOSCALER_MIG_CONFIG} ${CLOUD_CONFIG_OPT} ${AUTOSCALER_EXPANDER_CONFIG:-}"
+    local params="${AUTOSCALER_MIG_CONFIG} ${CLOUD_CONFIG_OPT} ${AUTOSCALER_EXPANDER_CONFIG:---expander=price}"
     sed -i -e "s@{{params}}@${params}@g" "${src_file}"
     sed -i -e "s@{{cloud_config_mount}}@${CLOUD_CONFIG_MOUNT}@g" "${src_file}"
     sed -i -e "s@{{cloud_config_volume}}@${CLOUD_CONFIG_VOLUME}@g" "${src_file}"