Last weekend my kid put a new intake manifold gasket on my '97 Lumina.
I was his helper.
This was about a solid 6 hour job. Count parts cleaning, putting a
new o-ring on the distributor/oil pump shaft, a beer and a nap,
running to the parts store, etc., it's more like 10-12 hours.
What makes changing a manifold gasket take so long to do?
On this 60 degree 6 the pushrods pass though the manifold gasket.
That means the pushrods have to come out.
I bought that 20 buck Lisle pushrod removal tool so we didn't have to
remove the rockers, which could open a can of worms.
Well worth it.
Disconnect batter, which right away means pulling the airbox, pull
lower hose to drain coolant.
Alternator has to come off, PS pump has to be hung aside, coil packs
come off, gas lines disconnected, throttle linkage disconnected,
engine brace off to pull the windshield washer tank.
Then you have about 6 or 7 vacuum lines, a few line hold down braces,
maybe 10 electrical connectors.
Every one of these lines and connectors stresses me, because I screwed
some up in the past.
Many you can't see well, so you have to go by feel.
They're a walk in the park for the kid, because he's just a better
mechanic. Besides something like 10/10 eyes, he's had a lot of
practice at boneyards. He knows every connector type and he didn't
break anything. Even had a fuel line disconnected tool, something I
never heard of. His first car had an older 3.1.
Then you pull the manifold heater tubes, upper plenum, valve covers,
Finally pull the intake manifold, and remove the pushrods.
Clean up, and put it all back together.
Add fresh oil and filter, warm it up and drain oil and replace oil and
filter again to make sure you removed the coolant that got in there.
I used to pull and replace the intake and both heads in the same time
on older cars.
Don't have the heart to tackle this new stuff.
I really think all the crap you have to do to get at this 3.1 manifold
gasket is a sign of bad design, especially since the original gaskets
were garbage, and commonly failed.
I helped the kid do the lower intake gasket on the 3800 in his '95
Bonneville and it was a much easier job than on the 3.1.
Like the Lumina, a badly designed original gasket that we replaced
with a revised version before it went bad.
OTOH, the components of these newer cars are most often better
designed than the old ones, the metallurgy is better, and failures are
much more rare, so I'm not really complaining.
No way I want to go backwards.
But man, the work needed to change that intake gasket on the Lumina
sure surprised me.