How can i get harmed and healed by diferent game objects

Hi, i recently watch a tutorial about health bars, and i successfully complete it, however i can only set two enemys (in this case "cars") one of the cars harm me when i crash with it (Game Object 2)and the other one heal me (Game Object 1).

What i want to do is put more than that two cars, but when i duplicate the car nothing happens when i crash it. heres a copy of the code, ignore the comments most of them are dead code that i didn't use. The code is in C#

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class CarPlus : MonoBehaviour {
     
     //variables
     float Speed = 10f;
     float rotation =50f;
     public RectTransform htrans;
     private float cachedY;
     private float minXval;
     private float maxXval;
     public int currentHealth;
 
     public int CurrentHealth {
         get {return currentHealth;}
         set {currentHealth = value;
             handlehealth();
         }
     }
 
 
     public int MaxHealth;
     public Image Imageh;
     public float cooldown;
     public bool cd;
 
 
     //aqui es para cambiar el texto, si es que se quiere agregar
     public Text healthtext;
     void Start () {
         cachedY = htrans.position.y;
         maxXval = htrans.position.x;
         minXval = htrans.position.x - htrans.rect.width;
         currentHealth = MaxHealth;
         cd = false;
 
 
     }
     
     // Update is called once per frame
     void Update () {
         //estos floats hacen que el auto se mueva, como es un jueguillo caca no es muy realista xD
         float trans = Input.GetAxis ("Vertical") * Speed;
         float rot = Input.GetAxis ("Horizontal") * rotation;
         //no recuerdo que hacen
         trans *= Time.deltaTime;
         rot *= Time.deltaTime;
         //Estas lineas determinan en que eje se movera el auto
         transform.Translate (trans, 0, 0);
         transform.Rotate (0, rot, 0);
         //transform.Rotate (0, rotd, 0);
     }
     private void handlehealth()
     {
         //healthtext.text = "Health: " + currentHealth;
         float CurrentXval = MapValues (currentHealth, 0, MaxHealth, minXval, maxXval);
 
         htrans.position = new Vector3 (CurrentXval, cachedY);
         //if (currentHealth > MaxHealth / 2) {
             //Imageh.color=new Color32((byte)MapValues(currentHealth, MaxHealth/2, MaxHealth,255,0),255,0,255);
         //} else 
         //{
             //Imageh.color=new Color32(255,(byte) MapValues(currentHealth,0,MaxHealth/2,0,255),0,255);
         //}
     }
     IEnumerator cooldowndmg()
     {
         cd = true;
         yield return new WaitForSeconds (cooldown);
         cd = false;
 
     }
 
     void OnTriggerStay(Collider other)
     {
         if(other.name == "GameObject 1" )
         {
             if(!cd && currentHealth > 0)
             StartCoroutine(cooldowndmg());
             CurrentHealth -=1;
 
             Debug.Log("Getting health");
         }
         if(other.name == "GameObject 2")
         {
             if(!cd && currentHealth < MaxHealth)
             {
             StartCoroutine(cooldowndmg());
             CurrentHealth +=1;
 
             Debug.Log("Getting harmed");
             }
 
         }
 }
     private float MapValues(float x, float inmin, float inmax, float outmin, float outmax)
     {
         return (x - inmin) * (outmax - outmin) / (inmax - inmin) + outmin;
     }
 }