seattlelexusguy,
I would suggest you get a copy of the Lexus service manual. Maybe someone will send you a copy of the procedure with pictures.
Here is a list of engine smoke anaylsis:
Blue smoke indicates that engine oil is being burned, if the smoke is coming from
the exhaust. If the smoke occurs during acceleration look at the piston rings as
it source. If it occurs during deceleration look at the valve guides as it source.
Black or very dark brown smoke is usually associated with an engine that is
running rich. You might want to look at the fuel injection system.
White smoke has two common sources, transmission fluid and/or antifreeze. Check
the vacuum hose, usually located to the transmission output shaft housing. I am
not for sure on the LS400, since I have not look. The service manual will be your
best source. If you see transmission fluid in the hose, replace the vacuum
modulator. If there is no tranmission fluid in the hose, then most likely source
of the white smoke is a blown head gasket, a cracked cylinder head, or a cracked
block. These conditions can be confirmed with a compression test or cylinder
leakage test (Best). Another way to determine whether white smoke is burned
tranmission fluid or burned antifreeze. The antifreeze has a distinct sweet odor,
whereas the transmission fluid just smells smoky.