My Grand Cherokee Jeep Overland has over 200,000 miles on it and it smokes some if you sit and idle for about 10. It also smokes a little when you change to reverse and start backing up. I would like to know is this is rings or valve oil seals causing the smoking?

 

Depending on which engine you have, try checking the head oil drains. If too much oil is retained in the head(s), it can cause the valve seals to be submerged in oil and suck it in. This is a common thing with SB Chevys but can happen to any engine. A good indication of this problem is valve cover gasket leaks at the rear.

Usually if it was rings, it would smoke all the time and you'd see oil in the air filter housing and CCV hose.

 

The engine is worn. How much oil does it use?