[JhnzRep]

PHP код:

new Float:CarHealth[MAX_VEHICLES];

forward CarChecker(carid);
public CarChecker(carid)
{
    new Float:health,string[70];
    for(new i = 0; v < MAX_PLAYERS; i++)
    {
        if(IsPlayerInAnyVehicle(i))
        {
            GetVehicleHealth(GetPlayerVehicleID(i), health);
            format(string, sizeof(string), "Your car lost %f HP!", CarHealth(GetPlayerVehicleID(i))-health);
            SendClientMessage(playerid, -1, string);
            CarHealth[GetPlayerVehicleID(i)] = health;
        }
    }
} 


Then just set up a timer under OnGameModeInit.