diff --git a/client/vaultclient/vaultclient.go b/client/vaultclient/vaultclient.go
index fce8dfc4390..ea221bba6c1 100644
--- a/client/vaultclient/vaultclient.go
+++ b/client/vaultclient/vaultclient.go
@@ -188,28 +188,36 @@ func (c *vaultClient) isTracked(id string) bool {
 	return ok
 }
 
+// isRunning returns true if the client is running.
+func (c *vaultClient) isRunning() bool {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	return c.running
+}
+
 // Starts the renewal loop of vault client
 func (c *vaultClient) Start() {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
 	if !c.config.IsEnabled() || c.running {
 		return
 	}
 
-	c.lock.Lock()
 	c.running = true
-	c.lock.Unlock()
 
 	go c.run()
 }
 
 // Stops the renewal loop of vault client
 func (c *vaultClient) Stop() {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
 	if !c.config.IsEnabled() || !c.running {
 		return
 	}
 
-	c.lock.Lock()
-	defer c.lock.Unlock()
-
 	c.running = false
 	close(c.stopCh)
 }
@@ -229,7 +237,7 @@ func (c *vaultClient) DeriveToken(alloc *structs.Allocation, taskNames []string)
 	if !c.config.IsEnabled() {
 		return nil, fmt.Errorf("vault client not enabled")
 	}
-	if !c.running {
+	if !c.isRunning() {
 		return nil, fmt.Errorf("vault client is not running")
 	}
 
@@ -499,7 +507,7 @@ func (c *vaultClient) run() {
 	}
 
 	var renewalCh <-chan time.Time
-	for c.config.IsEnabled() && c.running {
+	for c.config.IsEnabled() && c.isRunning() {
 		// Fetches the candidate for next renewal
 		renewalReq, renewalTime := c.nextRenewal()
 		if renewalTime.IsZero() {
diff --git a/client/vaultclient/vaultclient_test.go b/client/vaultclient/vaultclient_test.go
index d8094eb48ab..6f5ef6645cc 100644
--- a/client/vaultclient/vaultclient_test.go
+++ b/client/vaultclient/vaultclient_test.go
@@ -76,8 +76,11 @@ func TestVaultClient_TokenRenewals(t *testing.T) {
 		}(errCh)
 	}
 
-	if c.heap.Length() != num {
-		t.Fatalf("bad: heap length: expected: %d, actual: %d", num, c.heap.Length())
+	c.lock.Lock()
+	length := c.heap.Length()
+	c.lock.Unlock()
+	if length != num {
+		t.Fatalf("bad: heap length: expected: %d, actual: %d", num, length)
 	}
 
 	time.Sleep(time.Duration(testutil.TestMultiplier()) * time.Second)
@@ -88,8 +91,11 @@ func TestVaultClient_TokenRenewals(t *testing.T) {
 		}
 	}
 
-	if c.heap.Length() != 0 {
-		t.Fatalf("bad: heap length: expected: 0, actual: %d", c.heap.Length())
+	c.lock.Lock()
+	length = c.heap.Length()
+	c.lock.Unlock()
+	if length != 0 {
+		t.Fatalf("bad: heap length: expected: 0, actual: %d", length)
 	}
 }