Write-Up: Lower Intake Manifold (LIM) Gaskets

That makes either a GM fail. And the coolant suspect in the potential failure of both.
Cheese, all I've ever heard about the plastic gasket on RP is that it should be replaced.
Now I've an aluminum set in hand, and all of a sudden it may NOT be right.

Sean, we are talking about the coolant elbow, not the LIM gasket. Your aluminum replacement gasket is the correct part to replace the OEM plastic, which GM acknowledges was a defective design.

{in my best Gilda Ratner} Oh... never mind.
But that is good news.. more aluminum, less plastic. Unless is isn't.

denim wrote:

{in my best Gilda Ratner} Oh... never mind.
But that is good news.. more aluminum, less plastic. Unless is isn't.

I'd have to see an elbow... the right thing to do would be to coat the inside of the elbow with epoxy, then I'd just have to call BS on myself... 'cause if they did coat it that way it would not corrode unless there was a flaw in the coating.

Locally only the plastic is available at about $4.
Anyone know what the aluminum item is going for?

$8.50.

I paid $11 for my plastic one.

For those experienced with LIM replacement.
For many reasons, I haven't yet reassembled from the LIM project. Soon!
Here's the thing...although I've re-read the entire thread, I didn't find anyone having issues with reassembly of the plastic elbow. So, am I right to assume it's easy to place the manifold correctly on the new gaskets while trying to get that elbow stuck into it properly?
Seems very awkward.
Thanks in advance!

denim wrote:

For those experienced with LIM replacement.
For many reasons, I haven't yet reassembled from the LIM project. Soon!
Here's the thing...although I've re-read the entire thread, I didn't find anyone having issues with reassembly of the plastic elbow. So, am I right to assume it's easy to place the manifold correctly on the new gaskets while trying to get that elbow stuck into it properly?
Seems very awkward.
Thanks in advance!

It's a little awkward but not really. I've had worse...

you wouldn't be the first one who had to pull the LIM back off to fix the elbow. As long as you get the elbow lined up before you start tightening bolts you will be okay.

Thanks Deeks.

Think of it this way: the LIM will slide in the valley with the screws removed. This lets the elbow be removed while staying in place. Unfortunately, the plastic ends will likely be broken off inside the LIM:



Reassembly is opposite. Slide the LIM into the elbow, then insert the screws.

Wait! I thought it went together sorta like this:


And, yes, there's a piece of the elbow left in the LIM. I'll dig it out when I replace.
Thanks.

Wait, if I still I have your attention:
Are the two o-rings that feed the TB coolant from the LIM special? I ask because they didn't come with my new SC gasket. I was thinking I might have something suitable.

I prefer to put big dabs of rtv in the 4lower corners where the manifold gaskets meet the two end seals. Then I bring the lim in at an angle and get the elbow lined up, and lower the lim into place so I only mush it into the corner rtv once. I don't like to slide it away without reinspecting/gooping the rtv again.

Good point. I remember sliding the LIM out to disassemble, but looking at my assembly pics, I must have put the LIM on first, as deek described. In this pic, you can see the LIM is on, but not the elbow.

AA,
You also have the tensioner assembly off. I do not. My engine doesn't require a complete tear down as yours did. Can you tell me if I will need to remove that to assemble the elbow properly? It seems unlikely according to deeks.
I'd find this answer myself, but my manuals are with the car (not here).

The shop manuals will assume a complete tear down for this job. I think you can install the elbow into the tensioner (pointing up at 45º), then lower the LIM in at an angle, engage the elbow, then lower into the valley as deekster was saying. I also used pretty good dabs of RTV on the 4 corners.

When you have it all apart, it will make sense. The LIM gasket was a lot less complicated that I thought it would be.

Quote :

Wait, if I still I have your attention:
Are the two o-rings that feed the TB coolant from the LIM special? I ask because they didn't come with my new SC gasket. I was thinking I might have something suitable.

I may get flack for this, but I reused mine.

I just did my LIM gasket and I replaced the elbow with an aluminum one from ZZP. I was doing my power steering pump at the same time do I also took the tensioner bracket off as well. it made installation of the elbow a breeze. Here are some pics of the install:
Notice the milky oil..

Of course this is a must with the SC off

New gasket, RTV NOT applied yet.

I should have taken a side by side of the plastic and aluminum elbow but forgot, here is a shot of it installed.

All cleaned up with new injector O-rings, coupler, valve cover gaskets and LIM gaskets.

Wow, very clean. Nice job!

how did the whole job take you?

Honestly It's tough to say because I have a second vehicle and I just worked on it whenever I had some spare time. I also had some downtime when I was waiting for parts. And since I worked on it at my leisure I was able to get really picky and clean all the parts that came off. But I would say this could be done in a day if you have a basic idea of what to expect.

SC_Sailboat wrote:

But I would say this could be done in a day if you have a basic idea of what to expect.

4 hours, MAX

17 pages on this thread and Googling, still not clear if 95 Series 1 SC engines are susceptible to this lower gasket defect.

Any definitive answer?

Thanks,
Al

Hey Al!

95's are also susceptable to this. My car recently began showing coolant above the valve covers and Ill be replacing mine soon!

al_roethlisberger wrote:

17 pages on this thread and Googling, still not clear if 95 Series 1 SC engines are susceptible to this lower gasket defect.

Any definitive answer?

Thanks,
Al

I believe they are but for some reason it wasn't as big of an issue. They also used plastic intake manifolds on the non SC motors. FWIW this thread is in the Series II section of the forum so it's all about the SII - if you do the gaskets on your Series I please take pics along the way (and of the old gaskets) and start a thread in the Series I section on this topic.

OK, thanks for the feedback. Now what I can't verify (yet) is if there is an improved LIM gasket for the Series 1 as there is for the 2. Will have to research.

Thanks! Al

I think the reason it doesn't seem to be so much an issue is because there are just more Series II SC owning members reporting and replacing the gaskets, because there's knowledge of the issue. If you didn't know what to look for, this issue would likely slip by undiagnosed. The most likely symptom would be eventual misfire from a couple of fouled plugs. Solution: replace for $5 and drive another 20k miles. Make sure to change the oil frequently (3k). Not everyone's idea of a fix, but it works.

The LIM gasket issue isn't as bad a problem as some make it out to be. Yes, it should be fixed if you really care about your engine's long-term health, but I do stress "long-term", meaning your car can run fine for 200-300k miles on OEM plastic gaskets with little or no issues. Mine lasted 247k and still wasn't even close to being a serious issue. Engine performance was very good and no detectable drop in coolant level. Gaskets didn't look that bad for having that many miles. Inspecting the engine during rebuild revealed no sludge or other suspect problems.

I think it's great that we are aware of the issue, and replacing the gasket is the way to go for those wanting optimum performance and or extended oil changes - I'm glad I fixed it after the rebuild - or if your gaskets are leaking an unusually high amount of coolant. But if just daily driving the car and you don't mind inspecting the plugs each year, most can go a very long time without doing the gasket change, and you can do it without replacing the DexCool (great coolant, IMO). Reminds me of a car that burns 1/2 qt of oil between changes. Do you pull the engine and rebuild right then and there? Most of us would keep running and just keep tabs on the oil level until something more pressing comes along.