Lexus Repair: 1996 Lexus ES300, 1996 lexus es300, shape appearance

Question
Just purchased a used ES300 w/ 83k. Runs great and is in good shape appearance wise anyway. I brought it home and the next morning when I started it up *POOF*. Gray smoke comes out pretty thick and then slowly thins out to nearly non-existant over about a 4-5 minute period. (It did not smoke on the day I bought it)I took it back to the place I bought it for his guy to check it out and they are telling me they believe it is valve seals. It has the 1MZ-FE which I hear is known for gelling of the oil under circumsatnces due to lack of maint. I guess my question is doing a valve job and dropping the pan to check the bottom end going to solve the problem and how much does this typically cost? I understand that it depends on how worn the cams and such are but I'm just looking for a figure to base this on when I get the estimate. Thanks in advance for your help.

Answer
Hello Mark, The ES-300 is known for the valve seal problem that you have. I have seen many even well taken care of Es's do this. We charge about $1,100 to replace the seals. I do not think you will have any problems with the cams. If there is a lot of sludge in the upper end then you will want to have the oil pick up screen checked and cleaned also. You will not have to remove the cylinder heads to do this job.