Today at lunch I noticed a puddle under my rodeo. Didn't think much about it, i figured it was from a previous car. When I got home as soon as I shut it off it started making a hissing sound and leaking coolant. It appeared to be coming from the front of the engine. The coolant wasn't boiling so i guess it didn't overheat. I'm confused about the leak and where it is coming from.:banghead: It has 190k. I don't think it is the water pump, I changed it at 135k.

My buddies tell me to replace the thermostat. I pulled it out but it was in the open position and closed when it cooled down. It seemed like it was in good condition. I may just replace it anyway since I have to put in a new seal.

Any Ideas would help alot!:screwy:
Thanks!
Matt

Crawl under the truck and let us know where it's dripping from.

60k seems like a short lived life for a waterpump, but it's VERY possible from the details you're describing. Was it an Isuzu waterpump replacement?

Make sure you use an OEM Isuzu thermostat as well, aftermarkets don't keep it cool enough.

Sounds like the pump. The t-stat probably has nothing to do with it, as you suggested. Ton of hoses up front, but I guess you got a good look at the major ones. Be glad you're not dealing with this mess:
http://img.photobucket.com/albums/v380/surferfletch/Rickspictures166.jpg
You can see a couple of the smaller coolant hoses up front.

Thanks for the help.
I had my mechanic friend look at it today , He thinks its the little rubber hoses to the left of the thermostat that goes into the intake manifold. That makes sense because i saw coolant coming from around there.

I had a similar leak and it came out to be an o-ring on the 'crossover manifold' for lack of better terms. if you look at the top of the timing cover and there is some coolant there, chances are it's the same as mine. It is a manifold that either recives or feeds coolant to the heads and there is a tube that gets attached to it from behind and that o-ring at that attach point is what went out on mine.