The kids car had the first signs of UIM failure. Have new (stovepiped) UIM on hand, and everything tore down, ready for a saturday rebuild, so I went down to the dealer with the info from the tech info, for the aluminum frame LIM gaskets. The gal behind the counter was insistent that I needed to know if had the alignment pins or not.

I know my way around the fenders, And am pretty sure that I don't see any alignment pins. (no set drift pins in either the LIM or on the mating surface on the heads. Which leads me to:

1) Does it really not matter, because the non-alignment pin version will work on both applications?

2) What do you guys recommend in the corners of the gaskets? It is clear that from the factory that some black RTV was used. Any good RTV work, or some specialized GM part #? (I already have some high temp that I plan to use on the ends of the EGR pipe.)

3) After tearing this far down, am I stupid for not replacing the Vavle cover gaskets, which are not weepy? (Car is right at the 100K mark, and they have not been touched yet)

Advice appreciated!

Edit- This is not for the car in my siggy, for a 1997 NA, that my son drives

As far as I know, the metal LIM gaskets will work just fine for you. I don't know what the deal is with the alignment pins, but I'm pretty sure it'* irrelevant.

I'd use copper RTV (the orange colored high temp stuff) for the corners. 1 blob before you put the end seals on and one blob before you put the LIM on top.

If you got the extra 35 bucks to spend, and you're not planning on doing rocker arms or anything, I guess I'd go ahead and swap the valve cover gaskets out for peace of mind, but then again it'* not totally necessary...

Jr's3800 1995 L36


Highlander'* 1998 L36


These pictures show where the pins go. In 1997, (maybe mid-model year?) GM added locating pins to the rails for the LIM. Many with the older no-pin design block have used the newer end rail pieces that come with the aluminum-frame gaskets. They just let the pins hang over the rail. They seal fine, those pins hanging out there don't hurt a thing.

If the dealer now has an aluminum frame gasket with side rail pieces without pins for the older models, that would be fine. But don't let them tell you that your car cannot use the aluminum frame gaskets because their computer tells them so. We know better.

Nice pictures, thank you VERY much. Just for reference, this 97 does not have the pins. I'm glad you posted, because i was thinking the pins were somewhere on the face of the heads. (which now I realize is kind of silly, unless they were REALLY short, you would nerver get the lim on/off)

I'll hit them up tomorrow, and out of curiousity, ask them for the no pin aluminums. (when they cant find them, get the ones in the techinfo)

Thanks everyone!

Like Dr. Buttermore mentioned..it'* funny. It'* a mute point and your counter girl was putting you through unnecessary hassle, however on other parts..many little things like that do actually matter.

On my 97 I let the pins hang over and no one would ever notice.

On the RTV. If you purchase one tube of Ultra Copper (aka the copper one Dilcc mentioned) you'll never need another version of RTV, it covers all the fluids and temps that you should find on the car.