diff --git a/http2/transport.go b/http2/transport.go
index 0402766b21..589a18fe82 100644
--- a/http2/transport.go
+++ b/http2/transport.go
@@ -116,13 +116,13 @@ type Transport struct {
 
 	// PingTimeout is the timeout after which the connection will be closed
 	// if a response to Ping is not received.
-	// 0 means no periodic pings. Defaults to 0.
+	// Defaults to PingPeriod/2
 	PingTimeout time.Duration
 
 	// ReadIdleTimeout is the timeout after which the periodic ping for
 	// connection health check will begin if no frame is received on the
 	// connection.
-	// The health check will stop once there is frame received on the
+	// The health check will stop once there is a frame received on the
 	// connection.
 	// Defaults to 60s.
 	ReadIdleTimeout time.Duration
@@ -158,6 +158,14 @@ func (t *Transport) readIdleTimeout() time.Duration {
 	return to
 }
 
+func (t *Transport) pingTimeout() time.Duration {
+	if t.PingTimeout == 0 {
+		return t.PingPeriod / 2
+	}
+	return t.PingTimeout
+
+}
+
 // ConfigureTransport configures a net/http HTTP/1 Transport to use HTTP/2.
 // It returns an error if t1 has already been HTTP/2-enabled.
 func ConfigureTransport(t1 *http.Transport) error {
@@ -267,7 +275,8 @@ type ClientConn struct {
 	wmu  sync.Mutex // held while writing; acquire AFTER mu if holding both
 	werr error      // first write error that has occurred
 
-	healthCheckStopCh chan struct{}
+	hmu               sync.Mutex    // guard the healthCheckStopCh
+	healthCheckStopCh chan struct{} // A close-only channel to stop the health check.
 }
 
 // clientStream is the state for a single HTTP/2 stream. One of these
@@ -705,7 +714,7 @@ func (t *Transport) newClientConn(c net.Conn, singleUse bool) (*ClientConn, erro
 
 func (cc *ClientConn) healthCheck(stop chan struct{}) {
 	pingPeriod := cc.t.PingPeriod
-	pingTimeout := cc.t.PingTimeout
+	pingTimeout := cc.t.pingTimeout()
 	if pingPeriod == 0 || pingTimeout == 0 {
 		return
 	}
@@ -729,6 +738,8 @@ func (cc *ClientConn) healthCheck(stop chan struct{}) {
 }
 
 func (cc *ClientConn) startHealthCheck() {
+	cc.hmu.Lock()
+	defer cc.hmu.Unlock()
 	if cc.healthCheckStopCh != nil {
 		// a health check is already running
 		return
@@ -738,6 +749,8 @@ func (cc *ClientConn) startHealthCheck() {
 }
 
 func (cc *ClientConn) stopHealthCheck() {
+	cc.hmu.Lock()
+	defer cc.hmu.Unlock()
 	if cc.healthCheckStopCh == nil {
 		// no health check running
 		return
@@ -934,7 +947,7 @@ func (cc *ClientConn) Close() error {
 
 // closes the client connection immediately. In-flight requests are interrupted.
 func (cc *ClientConn) closeForLostPing() error {
-	err := errors.New("http2: client connection force closed because ping frame is not responded")
+	err := errors.New("http2: client connection force closed because ping frame was not answered")
 	return cc.closeForError(err)
 }