3100 lower intake leaking, tips needed.

[3100 MPFI]

Here is the GM ones. They are solid black, and have 2 small metal inserts on the side bolt holes to keep the gasket from getting crushed.

[dodgerunner]

Thanks for the pictures now I'm confused what to do. I think I might want to do the dealer ones after seeing how they are built and what happen to mine. .
Here is the one that was leaking. It split down to the valley.


Every one of the coolant ports look basically the same.

And yes I alway replace the oil pump o-ring. They leak on the Fiero distributors the same way. The o-rings done last forever.

Now I have to decide what I do.
Take the Felpro back and get the dealer ones or try the Felpro again without the rtv.

Update....
Took the Fellpro's back and got the GM lower. Looks like the spacer will be an improvement in the design.

[pontiac3100]

that looks straight plastic (the gm one). is'nt this the reaso they're leaking in the first place.
becuase the plastic softens and hardens and within all of this it cracks.....

[torq455]

the newer ones i think are composite, but not sure. mine just cracked, didn't crush like in the pix. just be sure to clean, clean, clean the LIM to the block with brake cleaner!! then use these revised torque specs:

This bulletin is being revised to change the model Information. Please discard Corporate Bulletin Number 03-06-01-010A (Section 06 - Engine).

Condition

Some owners may comment on an apparent oil or coolant leak. Additionally, the comments may range from spots on the driveway to having to add fluids.

Cause

Intake manifold may be leaking allowing coolant, oil or both to leak from the engine.

Correction

Install a new design intake manifold gasket. The material used in the gasket has been changed in order to improve the sealing qualities of the gasket. When replacing the gasket, the intake manifold bolts must also be replaced and torqued to a revised specification. The new bolts will come with a pre-applied threadlocker on them.

Notice

An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.

Diagonal bolts may require a crows foot to tighten.

Tighten

1. Tighten the vertical lower intake manifold bolts (1) to 7N·m (62 lb in).
2. Tighten the diagonal lower intake manifold bolts (2) to 7N·m(62 lb in).
3. Tighten the vertical lower intake manifold bolts (1) to 13N·m(115 lb in).
4. Tighten the diagonal lower intake manifold bolts (2) to 25N·m(18 lb ft).

Parts Information

Part Number Description Qty
89017279 Intake manifold Gasket 1
11588915 Intake manifold bolt - short 4
11588914 Intake manifold bolt - long 4

[tractorman]

I've done this LIM job on three vehicles, and in my opinion the problem lies in the fact that these gaskets are plastic. I'm sure that the new GM gaskets are improved... but they're still plastic.

Considering how much trouble this job is, I personally wouldn't put plastic gaskets back in. Felpro 'problem saver' gaskets are metal with rubber sealing beads. The heat-transfer issue is pure nonsense... there is VERY little metal-to-metal contact. The gaskets are made from metal that's about 1/3 as thick as those plastic gaskets, with fairly thick rubber sealing beads on each side. The only metal-to-metal contact is in the built-in tabs that prevent excess crush... similar to the improved GM gaskets.

But whichever improved design you choose (GM or Felpro "problem saver"), I wouldn't reccommend putting those old-style cheap felpro's in. You're just setting yourself up to re-do the job in a few years should you keep the car.

[3100 MPFI]

If you look at the ones that I posted, you will see 2 metal pieces on the top and bottom of the bolt holes on the sides. They are still plastic, but those 2 metal inserts keep the gaskets from getting crushed. I have had those in my car for 4 years or so, and I have reused them 5 times now (the lower intake has been off 5 times. They are still like new, and are not cracked at all.

[Rhedalert]

Pics when I did my sister's 3100. You can see the thickness of the rubber around every port. It's obviously going to be the same thickness as the plastic gaskets otherwise it won't line up or seal correctly. I don't know how much of a difference it would make having the metal support sandwiched in the middle.

Also the way the original gasket failed, they ALL fail like that.

[torq455]

don't forget to replace the oil pump drive o-ring! that gets brittle and cracks and looks like the LIM gasket is seeping oil!

at least the metal gasket won't crack.

[dodgerunner]

Well the dealer ones are going in for now. The tabs should make a difference.
The only problem solver set that Oreily's had was $90 for the complete set.

Also the dealer ones come with a different torque spec. They now say 10 Ft lb on all bolts. The is the third set of torque specs I have seen for the intake.
However the 10 ftlbs sounds like it might make since. Hopefully will last for another 50K or so.

[torq455]

yeah, then you finger tighten back down after 20K miles. point being, you do that and after some miles you can loosen the bolts by hand. the dealership did my Z24 years ago. when i got it home that day, i added about 90 degrees more to all the bolts.

[tractorman]

I'm sure that the GM gaskets will work fine- they've GOT to be better than the originals.

I reckon felpro metal vs. GM plastic is just a matter of preference.

Like I tell everybody before they do this job: if you take nothing else from this forum- remember this:

KEEP THEM PUSHRODS IN ORDER.

The intake and exhaust pushrods are different lenghths- get two of them swapped, and you'll make valves hit pistons. It'll do hundreds of dollars worth of damage in a matter of seconds. Don't even THINK about cranking the engine over unless you're absolutely sure that the pushrods are in their proper places. It's downright sad how often people ruin their engines this way.

I reccomend that once you get the pushrods, rockers, and intake in place, you crank the engine over slowly by hand- using a 1/2" ratched on the crank dampener bolt. Turn it slowly and carefully, and if there's a pushrod out of place, it'll 'clunk' to a stop without doing damage. Then you can find and fix your problem- worked for a friend of mine with his '97 Lumina.

+1 on the oil pump drive o-ring advice. GM sells a new and improved o-ring that seals better and lasts longer.

[pontiac3100]

i myself prefer for them to leal outward.
but why do some people get unlucky and heve em leaking inside the engine.

also i seen mines and the gasket is white.
i thought the engine was leaking through the lim but it was my radiator and i cleaned the gunk off the engine and so far knock on wood...no leaks.

[dodgerunner]

Will all done, so far so good. Am driving the car to work tomorrow before I turn it over to my daughter, must to give it a road test.

Are the Felpro problem solver gaskets available just by themself or do you have to get them in a complete kit?

Thanks to all for the ideas and pictures.

[tractorman]

I've only seen them in sets.

[Rhedalert]

I bought them as an upper/lower set. Not the entire kit that includes head gaskets and such.