I have a 1998 SSEi with 140,000 miles. I am thinking about pulling the intake manifold and replacing the gasket. From what i have read on this site these gaskets fail after 100k and I don't want to get stranded or cause major engine damage . While I have it apart should I replace any parts on the supercharger? I understand that the couplers tend to fail. Should I be proactive and replace it while I have the supercharger off or just let a sleeping dog lie?

First make sure you use the aluminum framed gaskets with the LIM.

As for the supercharger. You can check the coupler by simply moving the pulley back and forth and check for any slop or play. If none, then the coupler is fine. I would say change the snout oil. Look on your hood, underside, right where the supercharger pulley is. Do you see a stripe of oil? If so, the seal needs to be replaced. When you get the supercharger off, flip it over and look at the rotors. They should be black. You might see a few bare spots. But if you see huge areas with the black missing, then the needle bearings are going out.

If you need a good supercharger, I have 2 of them.

Definately change them... if your still running Dexcool... i feel for your engine.

I changed mine at 74k last July 4th... lower end failed, got a used engine with 88k on it and it was the same way on the intake gaskets. GM originals are crap, use the Felpro "problem solver" gasket kit, metal with rubber, not plastic with rubber

First is one from my original L67 GTP at 74k



This is from the replacement engine, no worries, she was torn down and built back properly before installation, this was just after removing the SC and LIM


build up from either sitting, or something causing it to cake up, some good cleaner and it was gone


The LIM Metal Gasket kit is a GM# 89017816 list at a dealership is $65
Supercharger gasket is #24503911 and lists for $13
but I would suggest while your doing it, best to change the Valve cover gaskets too, just to make sure you dont get a oil leak... 2x #24503937 for about $25 each
plus a throttlebody gasket, a gallon of coolant for what gets wasted, oil and filter (coolant pools into pan when the manifold is removed) and maybe 1 or 2 other things i cant think of right off the top of my head :P

good luck

thanks! I have the 24503911 supercharger gasket but, the number on my GM intake gasket is 89017825. Did I get the wrong LIM gasket? Are the ones for the non supercharged different? Maybe thats what I have.
Good idea about doing the valve cover gaskets while I am at it. I was going to change the coolant elbows while I am at it.

Got it all apart tonight. My intake gasket looks much like the one in the photo above. There is no oil on the underside of the hood but I only got 5 ounces of oil out of the snout. The coupler must be shot because there is about 10 degrees of play in the shaft. Should I replace the bearing and seal while I have it apart?
I bought the wrong valve cover gaskets. I did not realize the valve covers were different than the ones on the NA engine. There sure is alot of 'stuff'' on top of the supercharger! Hope I can get it all back together.

Got the supercharger apart. The section that holds the gears came apart at the same time. I was looking for the black coating on the rotors. When I sprayed it with throttle body cleaner the black stuff camer off! It looks fine to me the bearings seem very smooth.
I got the coupler from Intense ( super fast shipping!). They sent Loctite gasket maker with it. The instructions call for 'Klean and Prime' primer prior to using the gasket maker. Do I need the primer in this application? Do I need to use gasket maker on both joints?

I just clean the surface and put gasket maker on both. And you really didn't want to remove that coating. It'* not wrecked, but you will loose a small amount of performance. Right about 1 psi of boost.

Thanks Dan! I thought it was just the same black gunk that forms in the throttle body. I had a throttle body on my Park Ave that was so bad that the butterfly would stick in the closed position. I thought when it came to these things cleanliness is next Godlyness. Oh well, leason learned.

It'* OK, won't hurt nothing.

What exactly is that black coating anyways that gives you that extra 1 psi??