Write-Up: Lower Intake Manifold (LIM) Gaskets

Gotcha, agree completely. I'll just keep this on my list of things to watch for.

As I've mentioned in some other threads, I put about 25-30k miles on my commute car a year, so I do a lot of fluid changes and maintenance in a short period of time. That is always a good time to look out for these sorts of things.

.... may need to call Rockauto to see if there ever was an "improved" 2nd version of the LIM gasket for the 95 Series 1 SC engine. If so, I haven't seen one listed.

Thanks,
Al

Al - just a quick note. I replaced the lifters in my Series I L67 a few weeks ago for my Lesabre and when I opened the box for my new intake gaskets (Fel-Pro) I found that they appeared to be an updated design from the last set I got last year. They aren't aluminum gaskets like the Series II, and they have no reason to be, but they also came with a bunch of O-rings for various places, and a new gaskets for that side cover on the LIM. Something changed, and they do seem to be slightly better quality construction. I wish I would have taken comparison pictures.

AA wrote:

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 wonder if the difference is the non-SC motors - I have only seen full failure (hydrolocking) on L36 engines. I have seen some pretty nasty gaskets come out of the supercharged motor but haven't experienced a hydrolock.

That's a good point. I'd assume by the time it's gotten that bad, the owner would notice some loss of coolant (assuming the coolant level sensor is still functioning).

I want to clarify my above post - I think it's a good idea to swap out the gaskets if you have symptoms. But if no symptoms, or only slight hints the gaskets are leaking (spark plug residue), you could get by for a little while without much issue.

AA wrote:

That's a good point. I'd assume by the time it's gotten that bad, the owner would notice some loss of coolant (assuming the coolant level sensor is still functioning).

The one time I experienced a 'catastrophic failure' was 3 years ago while we were on vacation about 1000 miles from home. We had two cars fortunately - my brother and family was in their Park Avenue and it had been slowly losing coolant for a long time. But this night it sucked the rest of the antifreeze dry when the LIM gasket finally let go... they were driving a few miles behind us late at night on a back country road, we got to the hotel and they didn't. An hour later my cellphone rings from an unknown number - they had walked to a nearby farmhouse (no cell service) at midnight after the low coolant light had come on - he pulled over to check it out and it hydrolocked and wouldn't turn over. We were supposed to drive the ~1000 miles back to Boston the next day...

The hotel we were staying at also ran a self-storage unit in the back. They were very helpful trying to round up a local mechanic on a Sunday but no luck. They let us put the car in a storage bay so we could work out of the weather. We had to drive to two different auto parts stores to gather all the parts and tools we needed, about 70 miles to one store and 40 from there to the other store, finally back to the hotel to start working. Mid-job we discovered something else we needed so we sent someone else on another 70 mile run... but in the end we finished that evening and drove back home the next day no problems, and the car has (of course) been running perfectly ever since. So our trip was set back by one day and we ended up winging the job from scratch in the middle of nowhere!!!

(if you know Michigan we were in Pellston when this happened... not much there!)

HI Folks,
Since my Rivs aren't locally stashed, the lim replacement project is still in progress.
I got a SC gasket from Rock Auto. It didn't come with o-rings for the throttle body. They may have coome with the one I didn't buy
Anyway, anyone know a source for just these rings?
Thanks in advance!

I have a few sets, Sean. Just PM me your address and I'll send them your way!

Oh Baby!
Just need one set for 2nd gen SC, '98.
But that would be swell!

Would this gasket cause a big enough leak for my rough start/ idle? My car died at hwy speeds on Fri. since then ive changed the rad and all vac lines, and planning on this next. Im out of my daily driver and need my riv back on the road ASAP!!

Probably wouldn't cause your car to die at hwy speed. There's a better chance it's a fueling issue (failing fuel pump).

SES codes-
P0300 (random misfire)
P1864 ( torque converter/ clutch circuit)

Anything to do with manifold?

Nope.

P0300 = random
P1864 = transmission

How do i clean or what should I use to clean manifold once I got it off?

Does anyone know what the torque specs/sequence is for the Super charger?

I just changed mines over and now I see oil on the top of my transmission my feelings just got hurt

I finished mine everything is sealed and holding fine, just now my water pump sounds like its going out and and I still have the check engine light on..hopefully can pull the codes tomorrow.

well.. still random misfire. and oil light came on. and started a ticking sound, sounds like lifters are getting stuck or the sound is coming from under the engine exhaust??

Could be a cracked EGR tube. Inspect the tube, or listen for noise with a mechanic's stethoscope.

96rivie wrote:

well.. still random misfire. and oil light came on. and started a ticking sound, sounds like lifters are getting stuck or the sound is coming from under the engine exhaust??

I got a 96 too its our year bruh take heed... but get down and see its coming from the cat cause thats where mined is coming from running lean too long

Well, perfect scenario for me to share some pics with you guys. This is what can happen to your oil if you let your leaking LIM gaskets go for too long. This is a Montana that somebody traded in. The LIM gaskets on it are completely shot. The Radiator cap is white, the oil cap is white, and the Coolant Reservoir is coated with goo. I just wanted to post these for the people who have never actually seen this happen. It's a milkshake!!  

my milkshake!!! lol

Thinking bout doing this to my 96 riviera. Coming up on 200,000 miles. I have the fel pro LIM gasket. Do I really need a supercharger gasket? If so where can I get it, what is the part #? Do I need anything else other than some coolant elbows? Is the valve cover gasket necessary?

rodrivi wrote:

Thinking bout doing this to my 96 riviera. Coming up on 200,000 miles. I have the fel pro LIM gasket. Do I really need a supercharger gasket? If so where can I get it, what is the part #? Do I need anything else other than some coolant elbows? Is the valve cover gasket necessary?

Yes you will need a new S/C gasket.Dont forget to install the new O-rings that come with the gasket.

Get the metal elbows.

No you dont need a valve cover gasket if the current one is good.Yes you do need a new gasket if it's leaking.

Go to Rockauto and enter your info and you will find all the parts you need.

Clean all the manifold bolts with a wire wheel & put some thread locker on 'em.Not sure if the 96 S/C bolts need a little thread sealer paste put on em but it's cheap insurance to have a little on hand.

Obey all torque settings.If ya dont have a torque wrench,tite is rite.Too tight and youre doomed  

Ok thanks robo. Does this look like the SC gasket? http://shop.advanceautoparts.com/p/felpro-plenum-gasket-set-ms-95744/15780173-P?searchTerm=felpro+plenum+gasket+set#fragment-3

Well..yeah.