valve seal replacement

I'm not sure what you mean by a valve seal--are you talking about the valve cover gasket?

To answer your question, yes the valve stem seals can be replaced without removing the cyl. head, but if you are not a mechanic with the proper tools, you will not be able to perform this at home! I am a Honda mechanic that just bought a 2001 Rav 4 for my girlfriend and just found out on cold starts, car smokes for 5 seconds then gone. I am going to try and re-seal valve stems first.