when i replaced mine.. i just got a new tube.. cost me 6 bucks at auto zone... lot better than fussing withthe old one..

 

Exact same thing happened to me. I looked online and could not find anything on how to deal with this. Not looking for input, just posting what I had to do to fix this. This is an answer for some who need to know.

I live in Canada, winter roads are salted and vehicles rust.

The water pump bypass tube rusted out and "burst" right at the hose attaching to the heater core. I watched many vids on how to fix and remove, the host was badly rusted. The slight turning back and forth to loosen the o-Ring, wouldn't budge, yes i used pb blaster. After trying to get it loose, the tube simply broke right at the water pump housing. tried many techniques to get it loose and out, no go. To avoid damaging the housing i removed the water pump, not a tough job but annoying in -15 degree weather (C) not (F), lots of vids on how to do this.

From the inside of the water pump (see pic), you can see the end piece that broke off from the water bypass tube. Took my time, sprayed some pb blaster on it, and tapped it out with a socket. In the pics you can see the O-Ring was pretty much disintegrated, same with the water pump gasket in places. Cleaned all surfaces, installed new Dorman bypass tube and new water pump gasket, reassembled.

 

You posted in the second gen section with a different motor, Not to mention this thread is 13 years old.