Help Needed: Strange Noise in 2007 Legacy Wagon 2.0 B-Sport (Import from Japan)

[Haitao]

So, there's this weird noise coming from my car, especially when I'm accelerating at low speeds or in reverse, even if the car's not moving. And get this – it all started right after the folks at the shop replaced my thermostat and radiator. Pretty strange, right?

Here's the deal: they swapped out the radiator first, but then my car kept overheating. So, I had to go back and bug them about it, and that's when they decided to change the thermostat too. They said they did a drive test after that, but who knows if they really checked everything properly?

I'm not sure what exactly they did to my car. And I'm also wondering if there's any connection between their test drive and the weird noise I'm hearing. Maybe they didn't put things back together right, or they messed with something by accident.