diff --git a/pql/ast.go b/pql/ast.go
index 88095c49b..88af892ad 100644
--- a/pql/ast.go
+++ b/pql/ast.go
@@ -445,7 +445,7 @@ func formatValue(v interface{}) string {
 	case []uint64:
 		return fmt.Sprintf("%s", joinUint64Slice(v))
 	case time.Time:
-		return fmt.Sprintf("\"%s\"", v.Format(TimeFormat))
+		return fmt.Sprintf("\"%s\"", v.Format(timeFormat))
 	case *Condition:
 		return v.String()
 	default:
diff --git a/pql/parser.go b/pql/parser.go
index 3bc91a2ee..611294971 100644
--- a/pql/parser.go
+++ b/pql/parser.go
@@ -22,8 +22,8 @@ import (
 	"github.com/pkg/errors"
 )
 
-// TimeFormat is the go-style time format used to parse string dates.
-const TimeFormat = "2006-01-02T15:04"
+// timeFormat is the go-style time format used to parse string dates.
+const timeFormat = "2006-01-02T15:04"
 
 // parser represents a parser for the PQL language.
 type parser struct {