We have a 95 Trooper 3.2 sohc and and 89 with the 2.8 both in nice cond , As the 95 has the bad coolant leak, and I removed the intake manifold , replaced orings in those metal tubes put everything back together ran great but still leaking .There can be many areas where there can be a leak ,orings ,small hoses , gaskets for waterpump and rear of engine freeze plug etc. . Very difficult to find while apart because there are little hoses that have to come of to pull everything . My question is how to coolant preesure test will you be able to see exactly where the leak is ? or any other way ? this has been going on for a while now . The top of the block is full of coolant covering the lower coolant tube. I have never seen a coolant system like this very difficult to get to . Sorry for the long post but it has to be explained . Still like the Trooper but losing patience now. Thanks.

Check the hard lines themselves. When you go to change out the o-ring seals you tend to have to put some pretty good torque to get them out of their homes. This can lead to them cracking.

An Isuzu mechanic told Jerry Lemond about this just a while back, he had seen several trucks come back in just after having a thermostat and o-rings changed.

Joe

Thanks , It turned out the small hose to the left and downwards from the waterpump was leaking. It comes off the left side and tees into two other bypass hoses. Finally fixed right this time . At least I got in there to replace the orings anyway.

Glad you found it. I had a nasty leak on my '95 3.2l Rodeo that took awhile to find. In the photo at the URL, it's #23 - small hose - cost $45 2 1/2 years ago. Runs across the motor at the front from one head to another. Connects to a Tee. Hard to see unti you start looking for it and lots of fun to replace.

LINK