Not all sounds under the hood are a reason to start looking for a new vehicle! First things first, PULL OVER. I don’t know how many people call me while driving asking me if I can hear this? Diagnosing a sound over the phone is just not possible. My response is usually, PULL OVER and shut off the engine. I know tow’s are not cheap, but the other option is 10-20 times more expensive.
The problems can range from low oil, valve train noises, belts, bearings, road furniture, etc. As long as your fluid levels are fine, most of the time it is something minor. So relax and look under your vehicle for something leaking, then check your fluid levels starting with your engine oil. Check to see if your drive belt or belts are still there. Don’t try and check the fluid in your radiator while the vehicle is hot, it’s dangerous!
If your not comfortable doing any of the things. Call a tow and have a garage take a quick look to see what’s going on.