Lower manifold gasket observations

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Finally mined my way down to the lower intake manifold on the 3.4L engine in my daughter's 2000 Alero today. (By the way whoever out there said that he
can do this whole gasket change job in five hours has my utmost admiration and respect.)
What took me by complete surprise after the manifold was off was the minor pitting that was present in the gasket surfaces of both the head and the manifold around the coolant passages.
Is this pitting the cause of the notorious leakage on these engines or is it the gasket itself that fails?
Could it be that some component or combination thereof in the gasket material doesn't get along well with aluminum in the presence of coolant with heat and gasket clamping stress factored in? I'm not up on the various electromotive series present in this part of the engine. It would be interesting to find out what metals can coax aluminum to sacrifice itself for the existing conditions.
What theories do you have?
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Thank you.
You -did- keep the push rods in order, didn't you?

It's the gasket itself that fails.

How often was the coolant changed?
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Yes, heeding the numerous warnings posted by folks in this group I removed the push rods one at a time and marked each one using electrical wire markers. Placed these markers at the top of each rod so I knew which end was up.

I'll examine the old gaskets a little more closely in hopes of seeing what deteriorated on them.

Don't know for certain as the vehicle was bought used. However, my strong suspicions are that it was still running on the original DexCool until about two months ago when I flushed the system and refilled it myself out of concern for it begin overdue for a recommended change.
wrote:

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Good man!

Usually they are sheared apart at the silicone inserts, other times it's just that the lower manifold bolts loosen up and the gasket loses clamp.

Original coolant at that age with depleted additives would account for the pitting.
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Silver Surfer wrote:

I think Neil is pulling your leg. We (and I'm sure he) routinely do this job in under 2 hrs.
Ian
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Now I'm getting a real inferiority complex.

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Silver Surfer wrote:

Why? We do this for a living. We do it over, and over, and over...again. The person that tackles it for the first, or second, or third time, is doing well if it took them 6-8 hrs. Especially if you are simply a hobby mechanic.
Ian
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You are correct. There is still nothing out there that can replace experience like yours.

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Naaaah... It's he air tools. ;-)
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Ian, you gotta remember that I've had 2 heart attacks, 4 by-passes. I have 12 pins and an artificial knee in my left leg*, 5 pins in my right leg and had a broken back. *(left leg used to have 18 pins in it before the knee swap)
IOWs, I ain't as fast as I used to was.
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Geeze man! I'm impressed. I've never gotten it down to 2 hours. I've never tried to get it down to that, but that's certainly humping your way through this piece of work.
--

-Mike-
snipped-for-privacy@alltel.net
  Click to see the full signature.
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Mike Marlow wrote:

Yeah....but you probably remove the rear valve cover and loosen off the rocker arms.
Ian
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12mm Flare nut wrench?
I guess Lisle has a tool out now for the shortcut, no tool dealers around here anymore though.
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aarcuda69062 wrote:

I use an 11mm one that seems to work good. One of the guys in the shop has the special tool, and it works nice, but it's not particularly necessary.
Ian
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Curious, what brand is your 11mm? I can't get it to slip over to the end by the pushrod, but the 12mm works fine.
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aarcuda69062 wrote:

It's an old Craftsman wrench, 10mm on one end and 11 on the other. I think I bought this wrench back when I first started in the trade. Hardly use it because it's really a poor quality flare wrench. The Snap On flare wrenches are much better. But hey, it finally has found its niche in life
Ian
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Silver Surfer wrote:

The coolant has to be "fresh". It must contain available stuff that is more electro-negative than aluminum. Otherwise the free oxygen will attack the Alum and the Alum sacrifices itself to save any iron in the engine.
Lithium        -3.00 volts Potassium    -2.92 Barium        -2.90 Strontium    -2.90 Calcium        -2.87 Sodium        -2.72 Magnesium    -2.34 Aluminum    -1.67 Manganese    -1.10 Zinc        -0.76 Iron        -0.44 Copper        +0.34 Oxygen        +0.40
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Very interesting. Per my answer to a question in a previous post the DexCool was anything but fresh. A lesson learned perhaps. Thanks for the electromotive series info. Very helpful.
" Paul " <"=?x-user-defined?Q??= Paul

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Several nitpicking type questions. Hope you don't mind. I'm kind of anal when it comes to details like these.
Having trouble finding Loctite in my area for some reason. Everyone around here has Permatex. Does anyone out there have any qualms about using the Permatex "blue" medium strength threadlocker product for the upper and lower manifold bolts?
Will the Loctite or Permatex threadlocker stand up to the motor oil the four center bolts are exposed to?
Does the lubricating effect of the threadlocker significantly affect the torque being applied to the bolts? My thinking is that the bolts could be overtightened if the threadlocker reduces the thread friction.
I could order a new set of bolts from the dealer, but I'm trying to minimize the delay already created by my steep learning curve.
Is the same kind of stuff that the factory puts on the new and replacement bolts available over the counter? If so, what is the product name?
The center bolts for the lower manifold each have a flat washer with a rubber insert. They look like they would be hard to find. Will a dab of RTV under the bolt head help ensure a good seal upon reassembly?
The Right Stuff gasket maker says it sets up in about five minutes. I am slow and deliberate on undertakings like this one. Will the fast set time be a problem for me? If so the FelPro stuff that came with the gasket set might be adequate.
I bought a 10 mm crow's foot for two of the diagonal bolts. Do you correct for the length of the crow's foot when applying torque?
Has there been any change to the recommended bolt torquing sequence or to the two stages of torquing?
Thanks for indulging me on these questions.

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Anal is good, no point in having to do it over...

Go ahead, use the Permatex brand. Loctite is often used as a generic term for thread locker.

Yes.

The addition of Loctite to the bolt threads is taken into consideration when the torque value is specified. DO NOT over torque the bolts, you WILL distort the engine block and make bad things happen.

I've been reusing these bolts for years.

Hard to tell who sold it originally to GM, could just as easily be a Loctite product, a Permatex product or PermaBond (National Starch) What is important is that the thread locker meet the specs for the job. Your choice at hand certainly does.

Not a bad idea..

It won't go solid in 5 minutes, it may skin over a bit... With everything cleaned, scraped and ready to install, the 5 minutes shouldn't be a problem, apply the Right Stuff, grab manifold, set in place, then relax and start applying thread locker and loading the bolts into place. The 5 minutes is not the time you have meet to have all bolts torqued. As long as the manifold is down in place and contacting the Right Stuff, you'll be fine.

Yes. Don't have the formula off the top of my head since when I need to use a crows foot in a torque application, I use a Snap-On slide rule type calculator. Tho I must say, I haven't found the need here to use a crows foot.

Any changes from when the car was built will be included with the gaskets, follow -their- torque specifications. Go around at least twice with the final torque, some of the bolts first torqued will probably change value as the manifold is pulled down to its final position.

Glad to help.
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