Land Rover Repair: Repeating Oxygen Sensor Error Code, oxygen sensors, home mechanic

Question
My long at home mechanic replaced Bank 1 & 2 Oxygen Sensors (Sounded like 4 were replaced).  The mechanic cleared the code and drove it with no Check Engine Light.  When I picked it up and drove it .5 miles the CEL came on.  The Oxygen Sensors showed the same error codes.

Do you have any suggestions?  

He also suggested I add some Prestone Super Leak Stop because of a small hint of Antifreeze smell.  I added the Leak Stop at home let the truck idal for 10 minutes with heat on.  There was no heat being blown.  Drove to Dairy Queen with my son and the truck temperature began to rise and then redlined.  Again no heat was being blown out of the vents in the cab.

Do you have any suggestions besided change mechanics for this truck?

Answer
Many people assume an o2 sensor code means you change the o2 sensors.  If only auto diagnostics were that easy!  Most of the time, what the code means is that the o2 sensor signal is out of range.  That can happen for many reasons; the truck could be right leaner even missing occasionally.  You need to do the tests that are associated with the particular codes and see where they lead you.

As to the stop leak and overheat - stop leak should not make the truck overheat unless you poured in a lot.  If you did you will need to clean it out.  If not, you are low on coolant or have some other problem.  I would caution you that Land Rovers are very unforgiving when it comes to overheating.  Drive them when overheated and you usually end up with a ruined motor.