My 2000 Toyota Corolla has 130,000 miles on it and it runs great. I live at 1250 ft elevation, and work at sea level. I downshift going down my hill every morning. When I accellerate at the bottom I blow blue smoke for 3 seconds and almost engulf the car behind me. I never see smoke otherwise. I use a quart of oil about every 2000 miles (so I think all of it is at the bottom of the hill every AM). Is this rings or valve guides? Can I get by with just taking the head off for an upper engine rebuild?
It might be the valve guide SEALS, not the guides themselves, and you can probably replace them without removing the head.
Ditto to McP’s post.
When you use your engine to control the speed going down, the air passage through which the pistons draw air and fuel is restricted by the throttle plate, creating a high vacuum condition in the cylinders. If your seals are worn this vacuum can pull oil down past them and past the valves (when they open) into the cylinders.