Ryy515

I was wonderin if this sound is related to catalysator warmer aka. Secondary whatnow. My last audi made a same sound before completely failing and alerting every neighbour when i got to work. Im also new at this forum so be gwntle with me. Or just tell me that i am a complete idiot and should sell my car or jump off the bridge or smth. Jokes aside. I own a lexus 430 and iys hard to find any info about that. Best regards.. Joni from finland.

alextv

The idler pulley which is real easy to replace is probably the problem. Also change the serpentine belt while off as this can make a sound also.

BigBoomer

Welcome Joni,
Nothing to do with the exhaust system or the CATs/O2 Sensors.
As Alex said, it is most likely to be bearings in one of the things that run off of the V-belt like the Alternator, Air-Conditioning compressor, or one of the tensioning pulleys.
When cold the bearing is part seized and makes a whining noise, but as it warms up it completely unseizes and the noise stops.
The best way to diagnose that kind of noise is with a Car Stethoscope eg. https://www.ebay.co.uk/itm/363796797999

bradland

Check your power steering fluid level. The reservoir often becomes stained dark which disguises the appearance of the level inside.
If the fluid level is a little low, or if the fluid is old, it will often whine on cold start up.
The LS power steering system uses Dex III ATF not conventional power steering fluid.