I drive a 1998 Pontiac Sunfire 2.2L 4 cylinder and recently it’s been acting up. It started overheating about a week ago while I was sitting in it idling, so I quickly shut the car off and let it cool down for a bit. I was able to drive it home and flushed all the old coolant out, as it was due for a change anyway. I believe it started overheating because there was oil mixed with the coolant and was running through the radiator. After flushing it I put in distilled water and some radiator stop leak for good measure, then added more coolant. I was only able to add 2 of 3 jugs I was supposed to add, even after starting the car and letting the water pump run. The coolant was a red color at first but it quickly became a yellowish color and now it’s turned black and smells like oil when I look in the coolant reservoir. I’m going to get a new radiator but what other problems do you think this ordeal may have created and will need to be fixed?