Small composite elbow leaking Anti-freeze

I have just rebuilt the entire water cooling system on my 02 impala(3.8) and now anti-freeze is leaking from a small plastic elbow located just Behind the belt tensioner. It seems to connect the block and the water jacket where the heater hoses connect and also is the back plate for the water pump. Any suggestions or similar problems?

This is a common problem on GM cars with the na and sc versions of the SII 3800 engine. It is the heater bypass. The plastic 90 degree elbow goes from the lower intake to the tensioner assembly. You can get that at the dealer for around $10 or auto parts stores that carry the aftermarket version made by Dorman/Motormote for a little less. Motormite HELP PN: 47065. Also, you will need the two o-ring seals on the ends of the elbow. To properly replace the elbow and o-rings you will need to remove the alternator and the tensioner assembly.