I swapped out my water pump last week and noticed 2 days later my coolant was low, ended up being down a quart a day, so obviously something was wrong. Took it apart Thursday night and saw the O ring that goes in the back wasn't seated properly. Fixed, put it together, add coolant, coolant just pours out the back of the pump. Take it apart, re-seat a different way, this time i think it's holding, so i do the normal filling procedure, everything looks good. Friday I drive to movies and back, boom down another quart, it's leaking from the back again. Today I tried using the old O ring, still leaks. I've taken this stupid pump off 6 times and can't get it working. When it's together i can squeeze the upper radiator hose and watch coolant drip out where the O ring is, so I know it's not something else back there broken. Being 95 and humid today isn't helping my temper either!!

So, can I use some gasket maker or sealant on the O ring back there? or is there too much of a risk of stuff getting into the pump and gumming it up? Any one else had issues with this O ring leaking?

The green O ring here:

 

Not sure how helpful this is, as I have the s/c 5.0 v8, but when I replaced the O-Ring for my water pump I actually ended up getting (intentionally or not) the whole black plastic adapter (in yellow on that diagram), which came complete with the O ring (in green). The reason I mention it is I have a feeling there's another O ring on the inside of the plastic adapter where it pushes onto the pipe. Maybe it's this one it's leaking from?

From memory the black plastic adapter wasn't that expensive.

 

Do you remember how hard it was to install the adapter? Looks like it's only like $13 (assuming it's part # C2Z18658, the diagram below looks a little different than the one on the car now but I don't see anything else that comes close), I don't see how to reach it without taking the intake plenum off.

 

Nevermind, i didn't realize it just pulled right off. I had given it a test tug or two a few days and and it felt firm so i had figured it was screwed in or had a hose clamp or something. Now that I have it off and can use it on the pump I think I see the problem. When that tube is on the car and the O ring is on it, it's not being pushed far enough into the pump, there's a half inch gap between the pump and the lip of that tube. Now the question is how to I find a way to get leverage back there to make sure it gets pushed all the way in? Guess I'll play with that this afternoon.

 

I am a new member in this forum and came across your DIY water pump replacement post. First, congrats for doing it, I am sure it wasn't an easy job. I am about to do the same thing for my car and I am halfway through it, about to remove the pump. There is a 1/4" diameter 90 deg. Black plastic elbow that connects a tube to the pump next to the pulley, how did you remove it from the pump? I am afraid I might break it and I understand it is impossible get.
Also, any tips on the tube and o rings the connect behind the pump, it was a source of problems for you. Other observations on this job would be greatly appreciated.

Thanks again,

 

I would replace that pipe along with the seal with no gasket sealer.

 

Looks like Jag says pry it off with a flat head screwdriver?

 

That 90' tube was a pain at first, but after removing the pump so many times it got pretty easy. Just takes a small flat head screwdriver to apply pressure on the outer part, highlighted in purple on your pic, then pull the tube. It does take some force, but thank goodness the tube never broke for me.

I never was able to get the tubes behind the pump to properly seal. It was such a maddening process, i had that pump on and off at least 10 times but it would always leak back there. Once you get the pump mounted there's no way to get behind it to properly insert the tubes. I ended up having to take it to a shop, and they had the pull the whole intake off to get it to sit properly. I sure hope you don't have that bad of luck!

 

Wow, thanks for the update!