2001 Avalon engine noise

Have a 2001 Avalon with 100K miles. When cold engine started it makes a noise like the starter is not disengaging. When engine warm it make no noise. Dealer says it is top engine noise because oil has drained to pan. Don’t belive it. Thoughts?

Any sludge in the oil? I will check the oil religiously since this car has the sludge prone V6. Show it to an independent mechanic, just in case the dealer does not want to admit to sludge issues.