Toyota Repair: 99 Toyota Rav4, valve stem seals, toyota rav4

Question
2.0 ltr, 135000 miles...a great car....Blue smoke after sitting, sometimes after long periods of time, sometimes after only short period...Seems to only do it after startup...I have changed the PCV at mechanics suggestion and no change.. He says it is most likely valve stem seals...He is willing to replace them and said that he was not sure if they could be changed without removing the head...I noticed one of your earlier posts, same problem same vehicle, you said that they could be replaced without head removal. Could you you give me a quick outline of what he needs to do? He is a very good mechanic. Is this most likely the problem and is there any way to diagnose for sure? Any help would be appreciated.
Thank you.

Answer
The valve stem seals are the cause of the blue smoke.
They can be replaced without removing the head.
Both of the camshafts have to be removed
The intake cam gear is a two piece design and a service bolt must be installed in the gear before removing.
The cylinders must be pressurized so the valve don't fall into the cylinder when the springs are removed.
There are special tools available to remove and reinstall the valve springs.