It started this spring with over heating issues. Changed everything down to the radiator. The dash still says its over heating, figured it was a gauge issue or eletrical issue due to the fact that battery gauge and the warning lights will come on all the time at strange intervels. My daughter has been driving the car with no issues with over heating untill today. She left from a friends house about 35 miles away and about half way home the oil pressure gauge started dropping till it was red lined. When she came to a stop sign the car started running rough. It would idle up and down and serge. When she got home she left the car sit for a short while and tried to start it and it would start but would start hard and not keep running. The oil pressure drops and goes back up with giving it a little gas but the car hesitates when you step on the gas. We replaced the engine coolant sensor, relays, and fuses. Jumped the relays to make sure the fans were working and then took it to a garage becaue we were out of ideas. They checked everything over and replaced the radiator and commented there must be an electrical issue with the dash. Any ideas where to begin? We have been working on it since spring and my daughter needs the car for work( she is 17) Only paid 600 for the car but it was a steal at the time. We did have the car checked by a mechanic before buying it.

You may have a whole array of faults there and from what you have written I can’t work out whether it’s overheating or not.
You say you have changed everything down to the radiator, however to be honest that’s a little meaningless.
You say the car would start hard and not keep running and so you took it to the garage and they checked everything over and replaced the radiator. Why?
Does it still start hard and not keep running are the garage telling you that’s a dash fault?