It hapened to me on my 2 ls400. There is a valve on the power steering pump. is located on the lower part of the pump. it has two hoses one goes to the intake. I replaced two that I got from the junk yard, they workl fine. I'm pretty sure. I found about it becaus I was replacing the power steering fluid every week then I add a "stop leak" fluiud to it and stop leaking fluid and the smoke stoped. Good luck!
I'm not so worried about the smoke once in awhile, but my power steering pump leaks and I was capping off every 3-4 days. I went to Pep Boys to get more and the salesclerk said "put this stop leak in, it worked for my car" he did not have a Lexus. It made it worse, now I cap off 2-3 times a day. My step Dad said he used Prolong transmission fluid and it worked - he got it at Auto Zone but they don't have it in CA. What is your opinion - I have 225K miles and I know I need a new car but don't know which one to buy as I want good gas mileage!
Blue smoke is from burning oil, white is from water. It's likely you have worn valve guides or piston rings that are allowing oil to get into the combustion chamber when the engine is cold. As the engine heats up, this is less of an issue due to the expansion of all the metal in the engine, thus sealing up the internal leaks. The power steering system has a leak that needs to be addressed. You'll need to have someone perform some tests to determine the condition of your engine, and in the end it may need to be rebuilt. You can try using oil that is designed for engines with higher mileage, this may decrease the amount of oil leaking into the cylinders.
check the Air control valve on the bottom of the p/s pump. mine leaked and sucked p/s fluid into my manifold.. i removed the air valve, stuck and bolt in the hole and capped off the 2 lines that ran to the motor. no more smokeing!