Arriving 20-7- 2011 6am at Shanghai Pudong airport leaving 4pm same day do I have time for half day tour.

Since your time is so limited, I think you have no need to join a tour. You could have a general view of Shanghai City by yourself. You can take subway line 2 from the airport to the downtown area. You could have a visit to the Bund, Nanjing Road and Yuyuan Garden. Your next flight is at 4pm, thus you need to back to the airport before 3pm.