The answer to 'pipe repair making noise' is that a noisy pipe after a repair can be caused by a few common issues. The most likely culprits are air bubbles in the water line, loose fittings, or water pressure issues. The noise may sound like banging, whistling, or vibrating.
If the noise started after a recent plumbing repair, it's likely that the repair was not done properly and needs to be addressed. Air pockets can form if the pipes weren't flushed correctly, and loose fittings can allow water to move erratically and create noise. High water pressure can also make pipes vibrate and make noise.