Have a 99 LS with the 3.1. I've replaced the intake gaskets, water pump and t-stat, and it still leaks coolant pretty bad. Iwas suggested on another forum, that it could be the coolant elbow, but when i googled, alot of stuff for the 3.8, and not the 3.1. Does the elbow exist on the 3.1?

 

does the coolant leak onto the ground or your just losing coolant internally? if it's internally, it could be a head gasket. if it's on the ground, is it possible you didn't seal up the water pump correctly? it's a common mistake that happens to even the best of mechanics. it's also possible the tstat cover wasn't sealed up either, or even a leaking radiator...

 

Pressure test and find that leak.

 

A pressure test would be the best place to start...then your not playing the guessing game. Maybe you have a crack in your radiator.

 

I dont think the 3.1 has the "ELBOW" i'll check with my book and see what i can find. You could also be leaking from your heater core. Just a thought.

 

Definately not the radiator and the heater core is bypassed. When I chabged the drive belt, I f-ed up and took the whole tensioner off. Is it possible it could be leaking from behind the plate that the tensioner and the water pump mount to?

 

could be a bad hose / hoseclamp somewhere or a bad water pump, or a bad thermostat.... is it leaking onto the ground? try parking on a small tarp or peice of plastic overnight if you cannot tell.... you will be able to see about how much leaks out & where its dripping down to....

 

No tarp needed, exhibit a, theres no coolant pooiling around the l.i.m., its just dripping down onto the axle/sub-frame

 

hmmmm..... you know what..... my car is having a very similar issue, driping in almost the exactly same spot, as weird as thatis, and im really only noticeing that the overflow tank is going dry, so im kinda leaning towards that leaking..... is your radiator down, or just the overflow tank?

 

Both actually, radiator usually goes down first though.