Rocker arms making clicking noise when accelerating

Hi! This is Bo with Car Genius at RepairPal! We've got to help keep this Galant on the road! The clicking noise from the rocker arms during acceleration could indicate a problem with the valve train. It could be worn or damaged components. The severity of the sound worsening as the car heats up might suggest an issue with lubrication or clearance. I suggest getting the radiator replaced ASAP. Then I would have a chemical test performed to check for exhaust gases mixing with the coolant. The temp gauge not going past halfway could indicate a faulty thermostat or sensor. I'm really not sure how it's not overheating. If you have any other questions feel free to call us at 877-913-1554! We'll be happy to find you a certified shop in your area!