06 envoy xl rear coolant leak

[LOCKER28]

I have a coolant leak on the passenger side from a black rubber nipple. Could this be the heater core?

 

[DocBrown]

If it is, you may be better off bypassing the rear hear heat. Mine started leaking in the back and appears to have a clogged heater core. The new core is cheap, but its a newer design and you have to replace lines as well. $1200 - $1500 to have it done. I thought about doing it myself until I looked underneath. Far too much work. I'm not aware of a kit that allows you to splice in the connectors to the old lines, though that seems like a no-brainer for someone to come up with. So instead I disconnected the rear inlet at the heater control valve, then cut the return hose just on the inside of the left wheel. I ran a 5/8 in heater hose from the heater control valve to the return hose using an elbow joint to connect those two ends. Cost me $20.

EDIT:
Just found the following. Wish I had run across this before. But it won't be too difficult to reconnect everything if I need to.

http://gmtnation.com/f23/how-replace-rear-heater-core-without-conversion-kit-474/