diff --git a/src/saveload/oldloader_sl.cpp b/src/saveload/oldloader_sl.cpp
--- a/src/saveload/oldloader_sl.cpp
+++ b/src/saveload/oldloader_sl.cpp
@@ -402,6 +402,7 @@ static bool FixTTOEngines()
 			/* Default engine is used */
 			_date += DAYS_TILL_ORIGINAL_BASE_YEAR;
 			StartupOneEngine(e, aging_date);
+			CalcEngineReliability(e, false);
 			e->intro_date -= DAYS_TILL_ORIGINAL_BASE_YEAR;
 			_date -= DAYS_TILL_ORIGINAL_BASE_YEAR;