diff --git a/vehicle.c b/vehicle.c
index 4c27eaa4de..2d09e8db72 100644
--- a/vehicle.c
+++ b/vehicle.c
@@ -1442,7 +1442,7 @@ int32 ReplaceVehicle(Vehicle *v)
 
 	/* Check if there is money for the upgrade.. if not, give a nice news-item
 	    (that is needed, because this CMD is called automaticly) */
-	if ( p->money64 < (p->engine_renew_money + build_cost + rear_engine_cost - v->value)) {
+	if ( p->money64 < (int32)(p->engine_renew_money + build_cost + rear_engine_cost - v->value)) {
 		if (( _local_player == v->owner ) && ( v->unitnumber != 0 )) {  //v->unitnumber = 0 for train cars
 			int message;
 			SetDParam(0, v->unitnumber);