This is just a heads-up to all.
I spent a number of days chasing sporadic coolant leak, I traced it back to one of the coolant elbows. I had just replaced the elbow a few months ago, and was rather surprised that it had failed. After speaking with an aquiantence of mine who owns his own shop, he informed me that he has had a number of problems with the aftermarket elbows leaking in a similar fashion. I have the exact same elbows in a handful of vehicles with only this one failure. My tech friend highly recommended going with the OEM elbows in the future.
Figured this was information that some may find useful.
2000 SSEi Galaxy Silver...All the toys: K&N,Gutted A/B, Mobil1.
2002 Monte Carlo SS: K&N, ZZP DP, Mobil1.
2001 Suburban 2500: 496 BBC K&N, Mobil1