diff --git a/examples/alerts/alerts.md b/examples/alerts/alerts.md
index 953cd8d3fcb..291c97ae970 100644
--- a/examples/alerts/alerts.md
+++ b/examples/alerts/alerts.md
@@ -322,11 +322,12 @@ rules:
     severity: critical
 - alert: ThanosSidecarUnhealthy
   annotations:
-    description: Thanos Sidecar {{$labels.instance}} is unhealthy for {{$value}} seconds.
+    description: Thanos Sidecar {{$labels.instance}} is unhealthy for more than {{$value}}
+      seconds.
     runbook_url: https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy
     summary: Thanos Sidecar is unhealthy.
   expr: |
-    time() - max by (job, instance) (thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"}) >= 600
+    time() - max by (job, instance) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"})) >= 240
   labels:
     severity: critical
 ```
diff --git a/examples/alerts/alerts.yaml b/examples/alerts/alerts.yaml
index 4e110a54d5a..f4c6e8d2377 100644
--- a/examples/alerts/alerts.yaml
+++ b/examples/alerts/alerts.yaml
@@ -306,12 +306,12 @@ groups:
       severity: critical
   - alert: ThanosSidecarUnhealthy
     annotations:
-      description: Thanos Sidecar {{$labels.instance}} is unhealthy for {{$value}}
-        seconds.
+      description: Thanos Sidecar {{$labels.instance}} is unhealthy for more than
+        {{$value}} seconds.
       runbook_url: https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy
       summary: Thanos Sidecar is unhealthy.
     expr: |
-      time() - max by (job, instance) (thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"}) >= 600
+      time() - max by (job, instance) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"})) >= 240
     labels:
       severity: critical
 - name: thanos-store
diff --git a/examples/alerts/tests.yaml b/examples/alerts/tests.yaml
index 7aace50da6b..951dcec9b40 100644
--- a/examples/alerts/tests.yaml
+++ b/examples/alerts/tests.yaml
@@ -8,9 +8,9 @@ tests:
 - interval: 1m
   input_series:
   - series: 'thanos_sidecar_last_heartbeat_success_time_seconds{namespace="production", job="thanos-sidecar", instance="thanos-sidecar-0"}'
-    values: '5 10 43 17 11 0 0 0'
+    values: '5 10 43 17 11 _x5 0x10'
   - series: 'thanos_sidecar_last_heartbeat_success_time_seconds{namespace="production", job="thanos-sidecar", instance="thanos-sidecar-1"}'
-    values: '4 9 42 15 10 0 0 0'
+    values: '4 9 42 15 10 _x5 0x10'
   promql_expr_test:
     - expr: time()
       eval_time: 1m
@@ -22,112 +22,64 @@ tests:
       exp_samples:
         - labels: '{}'
           value: 120
-    - expr: max(thanos_sidecar_last_heartbeat_success_time_seconds{job="thanos-sidecar"}) by (job, instance)
-      eval_time: 2m
-      exp_samples:
-        - labels: '{job="thanos-sidecar", instance="thanos-sidecar-0"}'
-          value: 43
-        - labels: '{job="thanos-sidecar", instance="thanos-sidecar-1"}'
-          value: 42
-    - expr: max(thanos_sidecar_last_heartbeat_success_time_seconds{job="thanos-sidecar"}) by (job, instance)
-      eval_time: 10m
-      exp_samples:
-        - labels: '{job="thanos-sidecar", instance="thanos-sidecar-0"}'
-          value: 0
-        - labels: '{job="thanos-sidecar", instance="thanos-sidecar-1"}'
-          value: 0
-    - expr: max(thanos_sidecar_last_heartbeat_success_time_seconds{job="thanos-sidecar"}) by (job, instance)
-      eval_time: 11m
+    - expr: time() - max by (job, instance) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"}))
+      eval_time: 5m
       exp_samples:
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-0"}'
-          value: 0
+          value: 60
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-1"}'
-          value: 0
-    - expr: time() - max(thanos_sidecar_last_heartbeat_success_time_seconds{job="thanos-sidecar"}) by (job, instance)
-      eval_time: 10m
+          value: 60
+    - expr: time() - max by (job, instance) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"}))
+      eval_time: 6m
       exp_samples:
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-0"}'
-          value: 600
+          value: 120
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-1"}'
-          value: 600
-    - expr: time() - max(thanos_sidecar_last_heartbeat_success_time_seconds{job="thanos-sidecar"}) by (job, instance)
-      eval_time: 11m
+          value: 120
+    - expr: time() - max by (job, instance) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"}))
+      eval_time: 7m
       exp_samples:
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-0"}'
-          value: 660
+          value: 180
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-1"}'
-          value: 660
-    - expr: time() - max(thanos_sidecar_last_heartbeat_success_time_seconds{job="thanos-sidecar"}) by (job, instance) >= 600
-      eval_time: 12m
+          value: 180
+    - expr: time() - max by (job, instance) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{job=~".*thanos-sidecar.*"}))
+      eval_time: 8m
       exp_samples:
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-0"}'
-          value: 720
+          value: 240
         - labels: '{job="thanos-sidecar", instance="thanos-sidecar-1"}'
-          value: 720
+          value: 240
   alert_rule_test:
-  - eval_time: 1m
-    alertname: ThanosSidecarUnhealthy
-  - eval_time: 2m
-    alertname: ThanosSidecarUnhealthy
-  - eval_time: 3m
-    alertname: ThanosSidecarUnhealthy
-  - eval_time: 10m
-    alertname: ThanosSidecarUnhealthy
-    exp_alerts:
-    - exp_labels:
-        severity: critical
-        job: thanos-sidecar
-        instance: thanos-sidecar-0
-      exp_annotations:
-        description: 'Thanos Sidecar thanos-sidecar-0 is unhealthy for 600 seconds.'
-        runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
-        summary: 'Thanos Sidecar is unhealthy.'
-    - exp_labels:
-        severity: critical
-        job: thanos-sidecar
-        instance: thanos-sidecar-1
-      exp_annotations:
-        description: 'Thanos Sidecar thanos-sidecar-1 is unhealthy for 600 seconds.'
-        runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
-        summary: 'Thanos Sidecar is unhealthy.'
-  - eval_time: 11m
-    alertname: ThanosSidecarUnhealthy
-    exp_alerts:
-    - exp_labels:
-        severity: critical
-        job: thanos-sidecar
-        instance: thanos-sidecar-0
-      exp_annotations:
-        description: 'Thanos Sidecar thanos-sidecar-0 is unhealthy for 660 seconds.'
-        runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
-        summary: 'Thanos Sidecar is unhealthy.'
-    - exp_labels:
-        severity: critical
-        job: thanos-sidecar
-        instance: thanos-sidecar-1
-      exp_annotations:
-        description: 'Thanos Sidecar thanos-sidecar-1 is unhealthy for 660 seconds.'
-        runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
-        summary: 'Thanos Sidecar is unhealthy.'
-  - eval_time: 12m
-    alertname: ThanosSidecarUnhealthy
-    exp_alerts:
-    - exp_labels:
-        severity: critical
-        job: thanos-sidecar
-        instance: thanos-sidecar-0
-      exp_annotations:
-        description: 'Thanos Sidecar thanos-sidecar-0 is unhealthy for 720 seconds.'
-        runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
-        summary: 'Thanos Sidecar is unhealthy.'
-    - exp_labels:
-        severity: critical
-        job: thanos-sidecar
-        instance: thanos-sidecar-1
-      exp_annotations:
-        description: 'Thanos Sidecar thanos-sidecar-1 is unhealthy for 720 seconds.'
-        runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
-        summary: 'Thanos Sidecar is unhealthy.'
+    - eval_time: 1m
+      alertname: ThanosSidecarUnhealthy
+    - eval_time: 2m
+      alertname: ThanosSidecarUnhealthy
+    - eval_time: 3m
+      alertname: ThanosSidecarUnhealthy
+    - eval_time: 5m
+      alertname: ThanosSidecarUnhealthy
+    - eval_time: 8m
+      alertname: ThanosSidecarUnhealthy
+      exp_alerts:
+      - exp_labels:
+          severity: critical
+          job: thanos-sidecar
+          instance: thanos-sidecar-0
+        exp_annotations:
+          description: 'Thanos Sidecar thanos-sidecar-0 is unhealthy for more than 240 seconds.'
+          runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
+          summary: 'Thanos Sidecar is unhealthy.'
+      - exp_labels:
+          severity: critical
+          job: thanos-sidecar
+          instance: thanos-sidecar-1
+        exp_annotations:
+          description: 'Thanos Sidecar thanos-sidecar-1 is unhealthy for more than 240 seconds.'
+          runbook_url: 'https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy'
+          summary: 'Thanos Sidecar is unhealthy.'
+    - eval_time: 10m
+      alertname: ThanosSidecarUnhealthy
 - interval: 1m
   input_series:
   - series: 'prometheus_rule_evaluations_total{namespace="production", job="thanos-ruler", instance="thanos-ruler-0"}'
diff --git a/mixin/alerts/sidecar.libsonnet b/mixin/alerts/sidecar.libsonnet
index c5978163c12..4e21f0785ac 100644
--- a/mixin/alerts/sidecar.libsonnet
+++ b/mixin/alerts/sidecar.libsonnet
@@ -41,11 +41,11 @@
           {
             alert: 'ThanosSidecarUnhealthy',
             annotations: {
-              description: 'Thanos Sidecar {{$labels.instance}}%s is unhealthy for {{$value}} seconds.' % location,
+              description: 'Thanos Sidecar {{$labels.instance}}%s is unhealthy for more than {{$value}} seconds.' % location,
               summary: 'Thanos Sidecar is unhealthy.',
             },
             expr: |||
-              time() - max by (%(dimensions)s) (thanos_sidecar_last_heartbeat_success_time_seconds{%(selector)s}) >= 600
+              time() - max by (%(dimensions)s) (timestamp(thanos_sidecar_last_heartbeat_success_time_seconds{%(selector)s})) >= 240
             ||| % thanos.sidecar,
             labels: {
               severity: 'critical',
diff --git a/mixin/runbook.md b/mixin/runbook.md
index fc7d84c3b94..37d2a4ff7dc 100755
--- a/mixin/runbook.md
+++ b/mixin/runbook.md
@@ -86,7 +86,7 @@
 |---|---|---|---|---|
 |ThanosSidecarPrometheusDown|Thanos Sidecar cannot connect to Prometheus|Thanos Sidecar {{$labels.instance}} cannot connect to Prometheus.|critical|[https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarprometheusdown](https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarprometheusdown)|
 |ThanosSidecarBucketOperationsFailed|Thanos Sidecar bucket operations are failing|Thanos Sidecar {{$labels.instance}} bucket operations are failing|critical|[https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarbucketoperationsfailed](https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarbucketoperationsfailed)|
-|ThanosSidecarUnhealthy|Thanos Sidecar is unhealthy.|Thanos Sidecar {{$labels.instance}} is unhealthy for {{$value}} seconds.|critical|[https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy](https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy)|
+|ThanosSidecarUnhealthy|Thanos Sidecar is unhealthy.|Thanos Sidecar {{$labels.instance}} is unhealthy for more than {{$value}} seconds.|critical|[https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy](https://github.com/thanos-io/thanos/tree/main/mixin/runbook.md#alert-name-thanossidecarunhealthy)|
 
 ## thanos-store