I'm just finishing this same job on my 1997 Pontiac GrandAm. First of all, this is a known design weakness on these aluminum 60 degree "V" engines.....let me guess, it leaked coolant either to the outside of the engine, or more likely, into the engine where it turned the oil into a chocolate-colored froth.
Secondly, this job is non-trivial....takes a lot of tools, and a bit of know-how.....and you can get into big trouble with crossed, or stripped threads.....I say this because of the manner of the question leads me to believe that you've not done major engine work before...this is not a first-time job.
The general answer to your general question is that you remove the accesories (alternator and Power Steering pump, vacuum lines, ignition components, throttle linkage, cruise control linkage, MAP sensor, EGR stuff, etc.) and unbolt the intake manifold (upper and lower) sections, remove the old gaskets, clean everything up and reassemble with new gaskets. You need a torque wrench in the inch-pound range for the manifold bolts. Get a manual, and have someone there who is familiar with major engine work, or don't try it.
Best of luck to you
how to replace a distributor gasket on a 2000 Pontiac grand am 3.4l
$1000-$1500
Yes, you must install a new intake manifold gasket.
by the lower intake manifold while you are doing this you should replace the intake manifold gasket anyway because it will leak sooner or later.
Replace gasket why does gasket keep sliding
The only fix for a bad intake gasket is to remove the intake manifold and replace the gasket.
No. which manifold gasket are you wanting to replace? Intake or exhaust?
around 6-7 hours according to AllData
Remove the intake manifold retaining bolts from your 1996 Chevy Astro Van. Remove the manifold gasket and clean the surface. Reverse the process to install the new intake manifold gasket.
Pretty straight forward. You must remove the intake manifold in order to replace the gasket.
Elmo is cool
there is no lower intake gasket, only a front and rear gasket