My 2009 LS460 with 230,000 has developed a pretty loud noise from under the hood. Sounds like a combination of rattling, grinding, clicking, whirring. I can hear it when at idle if I open my door. Transmission shifts smooth, but noise seems to accelerate with rpm increase meaning it's not louder but the whirring gets faster. The engine temp is normal but a few months ago the temp spiked and display said overheat, but then returned to normal quickly. Spiked again a few days later and then returned to normal. I just had the front brakes replaced; mechanic installed new discs and stated my rotors are good.
I have only had the vehicle a year and a half and have driven it 8,000 miles. It was a one owner, dealer serviced prior to me.
Any ideas? Thanks!
