Hey, all - a few weeks after putting on new OEM engine belts, I started getting a "whistling" sound when the engine comes up to temperature and the engine is at idle speed. I have triple-checked my belt tension(s) and they are within spec. Using a mechanic's stethoscope, it seems like the noise/whistle is loudest between the thermostat and the water pump. Any thoughts as to why this is occurring? Here's a video of the sound:
