Purchase a SUV

I bought a SUV from this dealer in first week of September 2014 , one month later had to change all 4tires ( found 2 tires had fix flat) By the end of December had to change the CPU board ( computer) And now after 5 months from purchasing this nightmare SUV , I have it in a Shop waiting for engine replacement I called the dealer and want to know why he didn't told me about those issues because my mechanic Informed me that those problems was before you bought the car. All what the dealer have to say is SORRY , I think sorry can't help MR, don't try to be nice and screw up people ,be honest one time in your life