I have a 1984 Toyjota van and my toyata service book gives no info on working on the valves. With relatively low miles, 120,000 my van eats up the oil. It doesn't leave it on the ground and the compression checks out good. I am in the process of replacing my pcv valve but have my doubts that this will fix my problem. I had planned to remove my valve cover and be able to get to the valves to replace the seals, but my servece manual gives no procedure for this? John. Thanks