casting sand cause sludge in the cooling system

I brought the Chrysler 200 the year made 2013,in May of this year 2017. I had the oil changed from the dealership I purchased it from in April and then recently the first of December. Prior to this the car ran fine. A couple of days after getting the oil changed the car started to run hot. By that Tuesday I had to make stops so that I won't overheat and lock up on me. I called the dealership service department and told them what was going on. I had the car towed back to them and they said the problem was sludge in my coolant system and I will need a new radiator thermostat, replace the heating coil and the repair cost would be 2,000.00. I then called Chrysler's warranty department and that area of repairs was no longer under warranty. I had a friend pick my car up because I could not afford that kind of money, and he was willing to take a look at it. They explain to him that the reason the car had that issue was because the motor was made with casting sand which then gets into the coolant system. I looked to see if this was a recall issue and it is not so I am letting people know just in case someone else maybe going through this same thing. I was told that this issue can happen again even being fixed.