coolant dump

Where's all the coolant coming from? Having been steadily loosing coolant over the last few months I decided to replace the t-pipe o-ring again. I've changed it a couple of times and have never seemed to get it right. After trying to put a larger 0-ring in (wouldn't work), I replace the o-ring with the same size. After putting it all back together it all seemed to run fine. No leaks, nothing spraying out anywyhere.
I drove several miles and noticed steam from under the hood. I assumed it was the pooled coolant on top of the engine so wasn't real worryed about it. A few miles later the temp gauge spiked so I stopped and noticed coolant just pouring out, it seemed like from everywhere. I couldn't find or notice any particular or single place it was coming from, but it was all over the engine compartment.
The next day I took the air intake plenum off and checked the o-ring again. It appeared to be intact and holding a seal. Still no obvious place for a leak. I put it all back together making sure all hoses had new clamps and they were tight. Before putting the plenum back on I pressurized the system and noticed no leaks (I blew into the radiator and held it for as long as I could, I know, a crappy pressure system but it's all I had). So off I go again.
Virtually a repeat of the same thing. Ran fine and cool. I stopped after about five miles and looked under the hood and saw no steam and there was no coolant leaking from underneath. However two miles later, coolant dump. Again it was just pouring out. I wasn't in a position to really look close but it appeared to be coming from the rear area of the engine.
What do I do next?

There are a number of hoses near the manifold at the rear of the engine. See this post for a pic:

http://www.automotiveforums.com/vbulletin/showthread.php?t=761667

:) One of the 2 heater hoses?:) Andie

I was able to look up behind the engine today while it was running. It appeared that the coolant was pooling up on the top of the engine and running over, coming down the back of the engine. So it appears that the o-ring is the problem.
So, I've changed it three times already and have not been able to get it to work. What can I do different? How do I test the system before putting it all back together and running the truck?

You know there are 2 metal coolant pipes with o-rings, right?

What year??

It's a 93 with the 3.2l v-6. I wasn't aware of two metal pipes with 0-rings. The only one I knew of and addressed was the one running fore to aft between the cylinders. So, where would the second one be?

the part number for the o-ring I'm having trouble with is 9-09561-338-0. Is there a nifty way to check this without putting the air intake back together and running the engine? Also, are there any tricks to ensuring the o-ring seats properly?

In my '97 there are 2 metal pipes running between the heads. You can see the smaller of the 2 in the picture in the previously mentioned post. The bigger pipe has been removed and the smaller is still at the base of the thermostat housing.

Found that second pipe but determined that is not the problem. There was very little coolant between the cylinders. So it appears that the o-ring is installed ok and working. There is still a leak coming from the back area of the engine. How do I check where it's coming from if I cant see it?

There is a coolant crossover pipe at the rear of the V6, joining the cylinder heads.

Check out the pic in this thread: http://forum.planetisuzoo.com/viewtopic.php?t=15158

The seals on mine blew. Had it fixed by a dealer because I didn't have the time to even find the leak.

That's the water manifold. That is about the only other leak that I can think of, other than a cracked head, that'll leave coolant up top. If you don't have coolant up top anymore, consider a freeze plug at the rear of the engine. It would be between the tranny housing and the block, so you can't see it, but it drips down behind the engine. I had a shop take care of that. Twenty-five cent part and loads of labor!

I found it. Turns out one of the hoses at the front of the engine had a leak and was blowing coolant back over the engine. Replace the hose and problem solved.

Glad it turned out to be a cheap fix.