diff --git a/wp-admin/theme-editor.php b/wp-admin/theme-editor.php
index 5f29a408b..a84aebeb3 100644
--- a/wp-admin/theme-editor.php
+++ b/wp-admin/theme-editor.php
@@ -94,6 +94,7 @@ case 'update':
 			fwrite( $f, $newcontent );
 			fclose( $f );
 			$location .= '&updated=true';
+			$theme->cache_delete();
 		}
 	}
 	wp_redirect( $location );
diff --git a/wp-includes/class-wp-theme.php b/wp-includes/class-wp-theme.php
index c5eea5c24..85b4584af 100644
--- a/wp-includes/class-wp-theme.php
+++ b/wp-includes/class-wp-theme.php
@@ -154,7 +154,7 @@ final class WP_Theme implements ArrayAccess {
 	 * @access private
 	 * @var bool
 	 */
-	private static $cache_expiration = 7200;
+	private static $cache_expiration = 1800;
 
 	/**
 	 * Constructor for WP_Theme.
@@ -503,6 +503,9 @@ final class WP_Theme implements ArrayAccess {
 	public function cache_delete() {
 		foreach ( array( 'theme', 'screenshot', 'screenshot_count', 'files', 'headers', 'page_templates' ) as $key )
 			wp_cache_delete( $key . '-' . $this->cache_hash, 'themes' );
+		$this->template = $this->textdomain_loaded = $this->theme_root_uri = $this->parent = $this->errors = $this->headers_sanitized = $this->name_translated = null;
+		$this->headers = array();
+		$this->__construct( $this->stylesheet, $this->theme_root );
 	}
 
 	/**
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index 40cb5b4bb..8bfdd74a5 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -351,10 +351,9 @@ function search_theme_directories( $force = false ) {
 			return $found_themes;
 		}
 		if ( ! is_int( $cache_expiration ) )
-			$cache_expiration = 7200;
+			$cache_expiration = 1800; // half hour
 	} else {
-		// Two hours is the default.
-		$cache_expiration = 7200;
+		$cache_expiration = 1800; // half hour
 	}
 
 	/* Loop the registered theme directories and extract all themes */