Riverside Mitsubishi sale scam

On 02/28/01 I purchased a used 1999 Mazda Protege from Riverside Mitsubishi. 07/24/01, the car broke down, overheated. When I took the car to Riverside Metro Auto Group for repairs, I was informed that the car was still under factory warranty and there shouldn't be a problem fixing it. Riverside Metro then calls me to let me know that the car repairs will not be covered under warranty because the original radiator is not in the vehicle. When I purchased the car from Riverside Mitsubishi, I was not informed of this. If at the time of purchase, they had informed me that the original radiator was not in the car, I would not have purchased it because it would seem to me that the vehicle has been in an auto accident. I would not purchase a car that's been in an accident. When I confronted Mitsubishi about the foreign radiator, they tell me that they wouldn't have checked the car for this. In so many words, they basically told me that there's nothing that they can do. Not only do I believe that they knew the car had a foreign part, but I also believe it's previously been in an accident. I want Riverside Mitsubishi to inspect the car or do the research to find out if the car has ever been in an auto accident. If not, I want the results in writing.