Warranty time for the Montana ends up at around the 4.6-4.8 hr
mark. The Century would be a bit less, probably around the 4.2 hr
mark. When I'm motivated and everything goes right...I can do
the van's in about 2 hrs and the cars in about 1.5 hrs. When the
vehicles are off warranty, the Century would pay about 5.9 hrs
and the van's are around the 6.5-7.0 hr range.
At this point, no. I would go with the updated GM gasket
that has the metal pellets imbedded in the gasket at the
ends. If you can find aftermarket gaskets that have the
same design....they should work just fine. I'm sure everyone
is aware that GM's gaskets are most likely made by "one"
of the aftermarket gasket makers anyway.
I'm sure they're made by Victor-reinz:
A Dana company, sold through NAPA, Car Quest and many other independent auto
They have the aluminum pellets embedded in the ends and also have a
permanently tacky silicone adhesive in the package.
I hope this input helps?
Hello after my short hiatus to you Ian.
I don't know of a site. I have a few pictures myself, but I don't think
I have enough to put together a complete pictorial procedure. I can
do it off the top of my head with text if you want. On the vans, there are
two ways to do the job. The first way, you remove both valve covers, the
second way (much faster) you do not remove the rear valve cover, coil
packs, or alternator. Let me know if you want the procedure (pretty much
the same for both vehicles other then some space issues) and I'll see if
I can type it out.
Ok, I'll go over the basic procedure for the van.
First step would be to drain the coolant. This year, you
need a 1/4 inch square drive ratchet and preferably a short
extension. Use the 1/4" ratchet to turn the drain cock
counter clockwise about an 1/8 of turn, then you have to
pull the drain cock out while turning it further.
Next...pull the rubber hood seal off at the front of the
cowl area...then you can pull off that plastic piece that
covers the wiper motor area (passenger side of the
Pull the air filter housing and snorkel..usually, I find it
easier to remove the rubber section first, and then you
have more room to remove the air filter cover and air
filter. There are a couple of electrical connections on
the snorkel and the MAF sensor, unplug them...and then
follow that wire harness back and unplug everything else
on it, except where it plugs into the coil pack ( oh yeah,
I'm going to give you the "faster" version). So you should
have a couple more sensors at the throttle body, a red
connector at the evap solenoid and then a harness clip
at the coil pack. You can position this harness back over
the coil pack. Remove the front three spark plug wires at
the coil pack. Unhook all the clips that hold those wires
to the engine, but don't bother to take the wires off the front
plugs, just lay the wires over the front of the rad support.
Remove the vacuum booster hose at the upper plenum.
Remove the two bolts that secure the coil pack bracket
to the upper intake plenum (10 mm head). Now you want
to remove the MAP sensor which sits bolted to a small
bracket on the upper plenum right in front of the coil
pack. You will need a 7 mm socket or wrench to undo
the two long screws that hold it in place. Then unhook
the vacuum lines and the electrical connector and lay
the sensor and vacuum lines somewhere. Now you
can remove the upper plenum bolts. At the passenger
rear side of the upper plenum, there is a small brace that
goes from the alternator to one of the bolts in the upper
plenum. Get that brace off and then you can take that
one plenum bolt out.
Now go to the back of the engine, you need to find
the EGR pipe that comes up to the upper plenum and
EGR valve. The temptation is to remove the valve, but
don't bother. Just remove the bolt that holds the flexible
pipe to the upper plenum. There is also a small nut that
holds the Transmission filler tube to a stud on the upper
plenum. You need to remove that and push the filler
tube off that stud. There is also one nut at the throttle
body that holds a coolant pipe in place, remove that and
disconnect the two small throttle body coolant hoses at
the back of the engine there. At this point you should be
able to remove the upper plenum. Do "not" bend the
coil pack bracket up to give yourself clearance. This makes
it very difficult to start those bolts properly later on. Just
slide the upper plenum out from underneath it. You may
notice that I said nothing about the cables to the throttle body.
I do not disconnect them, just leave them on the plenum and
flip the plenum upside down and off to the side. It will just
Next, you need to remove the fuel rail and injectors. There are
two 10mm head bolts that hold the rail to the lower intake, and
one that holds the fuel lines to a bracket at the rear of the rear
head. Remove all three, carefully pry/pull the fuel injectors and
rail out of the holes. Take a close look at the injectors once
you have them out, any o-rings that have come off need to
be retrieved from the intake manifold area. Sometimes they
will just be loose, other times, they are stuck in the injector
holes. Again, I don't disconnect the fuel lines, just position the
rail and lines off to the side somewhere.
There is a heater pipe that goes into the lower intake at the
rear of the engine. You need to simply loosen the nut that
holds it to a stud at the rear of the rear head, and then
you can pull the pipe out of the intake. Note: replace
that o-ring seal.
There is also a heater pipe and bypass pipe assembly
that runs along the front of the front valve cover. That
is the same pipe that had the two small throttle body hoses
connected to it. Remove it, and either move it off to the
side, or disconnect the "quick connect" fitting (sometimes
they aren't all the "quick" and so I just leave them).
Now you can remove the front valve cover, if you need
room to get at the one bolt, remove the left engine strut
and you can get a run at the bolt. Then loosen the two
rear valve cover bolts that you can see. One will be
under the alternator, the other is under the coil pack.
In both cases, there is just enough room to completely
loosen the two bolts.
Now you have to deal with the power steering pump.
Remove the small plastic shield that sits right above
the water pump pulley (this just give you a little more
clearance for the ps pump pulley). Now, remove
the serpentine belt. Then remove the three bolts
that hold the pump to the engine, you can access
them thru the bolts in the pulley. They are 13 mm
bolts. Now, you must loosen the ps pressure hose
fitting at the pump. Use a 5/8 wrench and just
loosen it until the hose will be able to move. In other
words, don't completely remove the hose. Now, reach
your hand down the two ps hoses and you will find some
plastic clips that the hoses are in. Pop the Pressure
hose (left one as you look down at the two hoses) out
of the plastic clip. Now, you should be able to pull
the pump up and lay it down between the front of
the engine and windshield washer bottle. You may
need to fiddle with the rubber return hose, as there
is a bracket in it's way, you can move the hose around
At this point, remove the lower intake bolts (8 of them)
and the upper rad hose from the lower intake. The intake
should now slide out from under the rear valve cover. Trust
me, it comes out. Now you have to loosen the rockers
arms enough so that you can get the push rods out. The rear
rocker arm bolts can be reached, even though the rear valve
cover is in place. Just loosen each rocker arm just enough
to be able to remove the push rods. Keep them in order,
as it's important that you don't mix them up.
Clean up your gasket surfaces..etc. Then install
your intake gaskets to the head first, then the push rods.
Short pushrods to the intake valves, long to the exhaust
valves. Be meticulous about cleaning the front and
rear surfaces of the block and the intake manifold, as
this is where the RTV sealer goes. Also clean the joint
between the rear valve cover and the cylinder head and
where the intake manifold will meet the two of them. Do
not mess with the rear valve cover gasket, just make sure
it stays up in it's groove. Before you install the intake, make
sure you have a nice bead of RTV on the front and rear mating
surfaces, and put a dab of RTV in that corner where the rear
v/c and head and intake will meet. From there, it's pretty
well just the reverse of the removal procedure. Don't bother
trying to tighten those two rear valve cover bolts until you have
torqued down the intake manifold. Then they will just slide
right in. Also, when you install the upper plenum, you are
going to slide it back under the coil pack, and then engage
the EGR pipe and the throttle body coolant hoses. Take your
time here, and make sure everything is where it should be
before tightening down the intake bolts.
Hope this helps, and all goes well. The procedure for the
Century will be almost identical, other then the Trans dipstick
No problem. I did forget one thing (probably others too, but
this one stands out). When you re-install the fuel rail, make
sure that you lubricate the injector o-rings and the holes that
they will slide into. I use the silicone lubricant that we use
on brake caliper slides. If you do not lubricate these seals,
often you can peel them right off the injector as you install
them, which will result in a vacuum leak that will be hard
Unless it's changed, most of the engine gaskets for the big three are made
by Detroit Gasket. I know this because I use Hill Engineering in Chicago
Illinois to build custom equipment for our plant. Hill also designs and
builds special dies and tooling for gaskets for Detroit Gasket. So through
our relation ship with Hill I know that Detroit Gasket is an OEM supplier.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.