I have my annual service coming up and already scheduled to drop my car off in a couple weeks. For a little while now I’ve been noticing a rattle/grumbling noise right behind me that I think might be one of the belt pulleys. It’s intermittent but comes and goes and I notice it while I’m idling. I’ve been doing some research it sounds like it could be the water pump starting to go out but I wouldn’t rule out a pulley since they’re all right there by the firewall. Anyone have any thoughts? Video audio might be tricky but if you listen closely or with headphones, I swear there’s a little rattle or grumble coming from one of the pulleys.

Should I have my mechanic replace my water pump and thermostat? For all I know both are original but my mechanic has said it’s not needed based on past inspection. If anything I’d like him to inspect all pulleys regardless. Let me know if anyone else has experienced a similar noise. Thanks!