Compatiable Engines For A 2000 Rx 300

[demibear]

Hello, to make a possible long story short, I got basically had when I bought my 2000 RX 300 from a dealership. What Toyota engines are compatible with my vehicle? The current engine uses excessive amount of oil the engine uses...long drives+long time turned off = blue colored smoke grenade when turned on. And every mechanic I have seen about it have commented that it is beyond sludged up and needs to be replaced. The dealership offered to pay for "desludging", but no one is willing to do it under warranty.

The Lexus dealership gave me an estimate of around 8k to fix the issue. A couple mechanics estimated around 4-6k. But I figure the biggest cost is the engine. And anything without the Lexus name attached to it tends to be cheaper. I remember reading about the 1MZ-FE being used in several Toyota cars. Thank you for any information.