Q: honda civic emitting high pitched noise under engine

It sounds like your accessory drive belt is loose and needs tensioned. If the belt has too much slack it will squeal. Over time, the rubber belt wears out and stretches. If it has cracks or splits the belt will need replaced. A bad pulley could also be to blame, but usually has a squeak rather than squeal. With the engine OFF open the hood and touch the belt. Hold is tightly and see if it has slack. Also look for signs of something leaking onto the belt. If the belt is loose it needs to be adjusted. There are two tensioners on your engine for the two belts it has. Adjustments are torque sensitive and adjustments should only be attempted by trained technicians. If you need assistance, have a mechanic, such as one from YourMechanic, inspect your vehicle’s noise issue.