1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

LIM Issue Seems Likely

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Old 02-04-2008, 06:02 PM
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Default LIM Issue Seems Likely

Given the reputation of the head gasket, it seems less likely, but here'* the situation.
Noticed the oil pressure gauge was reading a tick lower (around the 30 PSI mark instead of straight up, at 40 PSI), so I checked the oil, and found that rather quickly, it needed .5-1 quarts. Weird, it was fine about two weeks ago. I pull the cap and find what looks a lot like condensed moisture on the inside of the cap...along with a distinct rust-like colored residue.

That sinking feeling comes.
I smell the cap, and it doesn't smell just like oil.
Next step, look at the coolant reservoir. Looks not so good. It appears as though there are perceptible remnants of "scum" on at least the forward (facing) wall of the reservoir...like that of scum left on a bathtub. Most likely oil, it would appear. Smells like the stale air you get when you open the valve of a bicycle tire. The level in the coolant reservoir, however, does not appear to have gone down (yet).

My first thought was that my head gasket is blown, and the oil and coolant are now freely mixing.

Second thought, "Crap."
No external symptoms that are visible around the supercharger, the head, or the block. Or here - everything on the outside looks pretty clean like this:

Now, I have read a great many threads that pertain to it, and I understand that with supercharged vehicles the LIM can still be an issue, is far more likely than the HG - and of the two possibilities, I would much rather it was the LIM than the HG.
First off, I'm changing the oil today.
Second: Acquire - LIM gasket, seal for the intake mani & get down.

Now, I want to be as prepared as possible for this so I can get it fixed and running again ASAP and in one mech session.
I would like suggestions for what else I may need. Somebody (WillWren, I believe) mentioned that some bolts that are used, are stretch bolts. In my experience, these have only been used in securing the head to the block. Is that the case here, or do I need to pick up a set of bolts to mate the LIM to the head?
In the process of dismounting the LIM from the head, would it be wise/easier/do I have to separate the blower from the LIM? Should I do it just to replace the gasket between the supercharger and the LIM? If so, what about those bolts?
Heater Inlet pipe?
Lower Temp thermostat? 160º is the trick piece, yes?
Spark Plugs?
Should I bother with the Injector seals?
Easier to replace the drive belt tensioner at the same time (sounds like bearings are wearing out)? Do the two pulleys typically come attached to the tensioner bracket?
What'* this I hear about using RVT silicone (Permatex, I assume) in addition to the gaskets?
I should probably replace the gasket between the throttle body and the blower, yeah?
Replace DexCool with Prestone LongLife (DexCool compatible) seems to be the popular lean when it comes to new coolant, yes?
Do I have to de-pressurize the fuel lines before I remove the fuel rail, or can that just remain affixed atop the supercharger? Do the fuel rail quick connectors seal the fuel lines when disconnected?
Any other suggestions?

Right now, I'm going to start looking for my compression test gauge - perhaps I can glean some more definitive information.

Oh yeah - are there any particular places that I should look for parts because they make great products and have great prices? Other than that, I'll probably just go to the dealer. Nevermind - Intense motorsports seems to have it all & is reasonably priced.

Thanks.
================================================== =====================
Can't find the compression test gauge - hopefully it'* just the LIM.
Old 02-04-2008, 08:29 PM
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Default Re: LIM Issue Seems Likely

Noticed the oil pressure gauge was reading a tick lower (around the 30 PSI mark instead of straight up, at 40 PSI)
Mine sits at 30 if the engine has been running a long time and it is at idle. What PSI do you get going down the highway?

I checked the oil, and found that rather quickly, it needed .5-1 quarts. Weird, it was fine about two weeks ago
First of all, let me say that a bad LIM gasket will not cause you to lose any oil, so you might have a leaky oil pan or such.

I pull the cap and find what looks a lot like condensed moisture on the inside of the cap...along with a distinct rust-like colored residue
The picture you posted looks like it was just oil, at least it wasn't like this

That sinking feeling comes.
I smell the cap, and it doesn't smell just like oil.
coolant I'm assuming?

Next step, look at the coolant reservoir. Looks not so good. It appears as though there are perceptible remnants of "scum" on at least the forward (facing) wall of the reservoir...like that of scum left on a bathtub. Most likely oil, it would appear.
are you running DEX coolant or the green stuff?

The level in the coolant reservoir, however, does not appear to have gone down (yet).
this is a very good sign.

Now, I have read a great many threads that pertain to it, and I understand that with supercharged vehicles the LIM can still be an issue, is far more likely than the HG - and of the two possibilities, I would much rather it was the LIM than the HG.
In the many years of this forum, we have seen maybe 1 or 2 cases of a blown head gasket on the 3800. The only reason for them to blow it is if they get superheated. 99% sure you DIDN'T blow your headgasket.

Somebody (WillWren, I believe) mentioned that some bolts that are used, are stretch bolts. In my experience, these have only been used in securing the head to the block. Is that the case here, or do I need to pick up a set of bolts to mate the LIM to the head?
No, those bolts are not TTY (torque to yield) bolts (stretch)

In the process of dismounting the LIM from the head, would it be wise/easier/do I have to separate the blower from the LIM? Should I do it just to replace the gasket between the supercharger and the LIM? If so, what about those bolts?
The supercharger has to be removed to get to 2 hidden bolts on the LIM. The felpro gasket for the supercharger is cheap (like $7), so its not a big deal. Those nots are not TTY either.

Heater Inlet pipe?
The heater hose elbows are easily gotten at Autozone in the Help section, part number 47065
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Lower Temp thermostat? 160º is the trick piece, yes?
160 is to cold, you want a 180

Spark Plugs?
Get some Autolite 605 copper plugs, they are cheap and work great for boosted applications

Should I bother with the Injector seals?
yes, they are also cheap, and good insurance.

Easier to replace the drive belt tensioner at the same time (sounds like bearings are wearing out)?
It would be the ideal time if you really think its going out.

Do the two pulleys typically come attached to the tensioner bracket?
depends where you buy it from, but I am going to assume yes. If you need to order the pullies separate, here are the part numbers

What'* this I hear about using RVT silicone (Permatex, I assume) in addition to the gaskets?
apply dabs of Ultra Copper RTV to the corners of the gaskets before installing the LIM.
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I should probably replace the gasket between the throttle body and the blower, yeah?
no need to.

Replace DexCool with Prestone LongLife (DexCool compatible) seems to be the popular lean when it comes to new coolant, yes?
NO, not the DEX compatible.. get the green stuff. it looks like this.


this is what you DONT want


Do I have to de-pressurize the fuel lines before I remove the fuel rail, or can that just remain affixed atop the supercharger?
No need to remove the fuel rail from the lines. Just remove the 5 bolts (4 on the bottom and 1 up top) that hold down the rail and simply lift it off. Then just move the entire assembly to the side while you work.

Do the fuel rail quick connectors seal the fuel lines when disconnected?
No, but you dont need to worry about that since you wont be disconnecting the rail or injectors.

Any other suggestions?
Yes, after you are done, refill the coolant with this procedure to ensure no air bubbles.

Right now, I'm going to start looking for my compression test gauge - perhaps I can glean some more definitive information.
I still don't think you have a bad HG
Old 02-04-2008, 09:32 PM
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Wow! That was extremely thorough.
1) Oil pressure gauge usually runs straight up (@40psi) with slight variance given speed & engine temp.
2) Yeah, a coolant sort of smell
3) Yes, it is the unholy DexCool! Red Death!
I'll have to see if Kragen has an equivalent for the coolant elbow.
Any recommended venders for the belt tensioner? Never mind, I read the rest of your post - looks like Sears is my huckleberry.
I'll just pickup the FI seals at the stealership tomorrow - can't cost that much there.

Thanks!
Old 02-04-2008, 09:56 PM
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oil pressure sounds normal, thats good.

Never heard of Kragen before. When you tell them what you want, dont call it a coolant elbow, call it the heater hose elbow.

You can either get the tensioner at the dealership, or most parts stores will also carry it. I myself would get a used unit as it will be much cheaper. Check out www.car-part.com
Old 02-04-2008, 10:46 PM
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Hey, I didn't recognise you with the bitchin new avatar!
Kragen Auto Parts , Schuck'* Auto Parts, Checker Auto Parts, and Murry'* Discount Auto Stores have the same parent, just different regional branding.
I think I'll just try getting the pulley itself, instead of the entire apparatus...it sounds like the bearings are shrieking in pain once they warm up.

So was that rotten-apple-in-the-radiator picture your ride?
Old 02-04-2008, 10:53 PM
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no, that was wjcollier07'* 98 SE, nasty.
Old 02-04-2008, 11:18 PM
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Yeah...I hope I never crack mine open and see that!
Do you know if the supercharger O-ring seals are something that I can replace without having everything torn apart? Where do they even go?
Oh yeah - can you think of any special tools that I may need for this procedure? That includes Torx drivers - I may only have a 14 & a 16.
Old 02-04-2008, 11:28 PM
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if you are talking about the yellow o-rings that go between the supercharger and LIM, they go right here. They are a step you can't bypass.

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If you are talking about replacing the seals inside the SC nosedrive, its a completely different story. Lets not get into that.

Special tools? Just grab a socket wrench and your 10mm, 13mm and 15mm sockets. You will need a torque wrench to tighten the LIM bolts. Never heard of a 14 and 16 torx driver, but you might need a T47 to get the belt off.
Old 02-04-2008, 11:40 PM
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YES! Those are exactly what I'm talking about! I'm very glad I asked.
Where do you get these pictures that apply exactly to what I'm referring to so fast?
Glad to hear it about the tools...the belt doesn't scare me...I'll just ape that bit off, real Rambo style, yeah.
..now getting it back on..

Thanks again, homie!
Old 02-05-2008, 01:01 AM
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I take pictures of almost everything I do to my car, and I know where each one of them in posted. Search helps immensely


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