Hi,
If it doesn't happen at highway speed, it has something to do with the cooling fans or something is restricting airflow.
Inspect the radiator to make sure it isn't blocked or dirty. If it's dirty, clean it with a garden hose.
Next, when you turn the A/C on, you should hear one of the fans turn on. Is that happening?
Let me know.
Joe
Monday, July 3rd, 2023 AT 9:17 PM