Critical L36 Upper Intake Manifold Info....for 2000+ owners
 

Maybe you thought like I did that the problem ended in 1999. That was either a rumor or a false hope.

I have in my lap the AC Delco UIM off of EK98's car. His is obviously a 98, but his upper (second one on the car) was manufactured on:

March 2nd, 2002 <<<<<<remember this date while you look at the EGR passage in the pics below:

Attachment 59071

Attachment 59072

Attachment 59073

I firmly believe it's only a matter of time before we start seeing more NEWER cars, particularly 2000 and newer begin to fail. Be VERY watchful of your idle quality, smell of the exhaust, and coolant levels.

Bill...This may be one to toss into the 00+ mechanical area with a link..

I understand you put it here for better exposure. ;)

I put it here because it relates to 1995-2005 (and even newer GP's, not to mention the various Buick and Olds owners here).

Bill, are we positive that is a replacement ACDelco part?

It is an AC Delco. Identical to every production L36.

Delco manufactured in 2002.

Dumb question, but does the Shortstar (3.6 V6) have this problem as well?

I have 30k on my Dorman on the '96 SE and so far so good.

Not that we know of. But, we don't follow that engine as closely as we do the Bonneville power plants.

This doesn't surprise me in the slightest. The replacement manifolds made after 2000 don't have any more real protection than the originals, unless you consider a little heavier plastic material around the coolant passages sufficient.

As far as I know, there was no better EGR standpipe protection provided.

That is why I took the opportunity to stock a replacement UIM while I could get a good deal and have the time to properly shield the passages from the EGR pipe. This even though my UIM replacement by dealer was done in 2004 with a 2004 vintage UIM.

My uim was manufactured like in 2003 went out 3 months ago fixed with a one that is supposted to stop this problem.

Ive done a pretty fair amount of research on the 3.5 and I dont know of any problems with the UIM or LIM gaskets, or any common engine problems at all for that matter.

It does have the same composite UIM though, but the problem with the 3.8 is a design flaw, not because its made of composite material.

Running the EGR through the area of the Composite they did was deffinitely a design flaw... I saw how the L27's was designed, and wondered what they were thinking when they were developing the L36

Also family member deals with a series of the dealerships local to him and lately they have been seeing more of the 00-02's come in with upper intake failures... One was an 02 SLE and the guy was a friend of his... iirc the car had 52k on it at the time and popped while going up and onramp

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intake 1997
 

i have a 1998 regal whit 113,000 km on it the intake is original 1997 stamping i know this car as not been driven hard before but does the fact that in montreal the weather is colder help these intake to last longer i have a dorman intake that i will sleeve just in case don

I think there's some confusion here. Either I'm confused, or we're missing a vital detail.

I don't think anyone ever claimed that the 2000+ models were safe from UIM failure because of a change made to the UIM itself. The remedy for the problem, introduced in 1999, was a different LIM with smaller EGR bore and stovepipe. The LIM difference is what keeps the late model cars safe, not a difference in the UIM.

For this reason, I don't think it matters when EK98's UIM was manufactured. What matters more is the size of his EGR stovepipe. He could be running a brand new AC Delco UIM, and it wouldn't matter if he had the larger-bore stovepipe. This is likely the case, being that he drives a '98 and most likely has a '98 LIM. If he had a '99+ LIM, it might be cause for concern.

Again, to reiterate, I am under the impression that the date of UIM manufacture has little to do with UIM failure. It has more to do with the vintage of the LIM, because the '99+ models had the smaller EGR bore for more insulating air gap. A '98 LIM will generally compromise any composite intake, regardless of manufacture, due to the larger EGR stovepipe.

We've already seen 2000 cars fail the UIM here, and have reports from known mechanics that they're starting to see them too. It may be delayed due to design changes, but it's still beginning to happen.

<raising hand>... victim here... most likely twice over. I replaced the UIM & gasket (and LIM gasket) at 59k miles this past June. The date stamp on the UIM was 2002.... my car was made in June of 2000... :roll: :?: :shock:

Which is why I FIRMLY believe that the Dillon intake produced here, coupled with the Buttermore reduced-diameter stovepipe (produced here also) are the BEST solution to the problem, but only when USED TOGETHER. In addition, either purging the DEXcool for a more mild coolant and/or using the aluminum framed LIM gaskets is the insurance you need on an L36.

How many have seen the sad state of the OEM LIM gaskets? The degradation is a direct result of the poor qualities of DEXcool. The plastic actually erodes.

My recipe for L36 longevity (yes, I've experienced it personally on an L36):

1. Dillon intake. Unless Dorman starts sleeving them, this is the ONLY intake to buy.
2. Buttermore reduced-diameter EGR stovepipe.
3. New AC-Delco ALUMINUM framed LIM gaskets.
4. GET THE DEXCOOL OUT OF THERE!

With these 4 (in my opinion) taken care of, for a grand total of UNDER $200, you will not run any more chance of losing an engine than any L27 or L67 on this Forum.

I was just trying to point out that the supposed "safety" of '99+ L36 cars doesn't have anything to do with the build date of the UIM. Those cars were supposedly better because of the revised LIM. Whether they actually are better or not is questionable.

Bill, do you not like the APN intake? It comes pre-sleeved from the factory.

Why would I like or prefer that one? The Dillon intake is only $60.

My previous question about the APN unit was in regards to this statement:
I was just making sure the APN option was well-known. And yes, I agree that the Dillon unit is much more cost effective. However, if a person wanted a brand new intake for some reason, the APN UIM might be a better choice than the Dorman (at this point in time, anyway).

I was also asking about the APN unit because I thought there may be something about the design that you didn't like.

I've never seen an APN. But I have seen a Dillon. Had it in my hands, and installed it. It was a great opportunity to really see the possibilities. I can tell you there's simply no way it will fail in the EGR port area, particularly if coupled with a buttermore stovepipe.

I firmly believe it's a permanent solution IF it's done correctly, and that it can be done for under $200 total (not including labor).

oh jeez... my bonne is 7 years old and I sincerely doubt that ANYONE has ever checked on that (given its past owner...). how much does that cost to get replaced? and so there's NO way to end the cycle even after I replace the... lessee... upper intake? right? :?

because i CERTAINLY can't do it myself :oops:

Where do you live?

Maybe a local member can help.

That'll work just fine. That's what we do. ;)

Actually, the aftermarket replacement kits are getting better all the time and we have a member, Bob Dillon, who rebuilds/modifies old UIMs in a manner that should prevent or at least seriously delay any future failure.

Additionally, the LIM gasket failure can now be eliminated by using the newly available GM aluminum-framed gaskets for about $60 at your local Pontiac dealer.

Costs will vary for the UIM replacement kits and all gaskets and seals, depending on which one you get and where you get them.

I live in OH, Cincinnati area.

Just had mine replaced at 57,000 ('01 SSEi). Dealer said the gasket was leaking so they changed it. Gotta love that extended warranty...

This topic doesn't relate to the L67 engine in an SSEi. We're talking about the PLASTIC upper intake manifold of the L36.

As recently discovered on my wife's '97 LeSabre

While yesterday, I discovered that there was a replacement made to my UIM, for it has a manufactured date of 3/23/03. And the issue has returned.

alright.. so i checked for initial signs (at least from what I have read)..

the coolant is at the cold fill line (haven't driven in 5 hours)
the coolant is still pink (although maybe a hazy dark pink)
the dipstick just smells like oil and gas (nothing like coolant)
the engine cap was dry, but sticking my nose down in there i percieved a very faint hint of coolant.
engine runs just a half-tick below 200 on the temperature gauge unless at a long stop light, then it just touches the right side of the 200 hash.
the oil on the dipstick is very clean, honey colored (oil changed about 150 miles ago by the dealer before I drove it home)

does this sound all normal or no?

2004 SE, 39,200 miles

Assuming all is well right now, how soon do I need to worry about changing the LIM and UIM?
I'm a mechanical know-nothing, how much labor involved at the shop if I buy the parts that I've been reading about on here?

...

Danny...anywhere from 60K -100K is the normal failure area for the manifold. I've seen one come off a 2000 at 110K with no signs or issues. It's a big questions as to when or who.

GMC.. Prestone Long Life is a good one, as is the green stuff.

great, hopefully i'm safe then.

for the record, i'm going to have a coolant flush done tomorrow. it doesn't look like the dealer did it (probably not, since GM doesn't recommend it). My mechanic uses the green stuff. just short of 40,000 miles, will this potentially help me avoid the UIM/LIM failures or is it still just a matter of time in most cases?

That's a tough one. Many believe Dexcool is the cause of the deformed gaskets etc. However... more thinking on it..showed me that the gaskets fall apart in areas where there is no coolant. And GM has begun producing a different gasket ... not a different coolant. While Dexcool is obviously not the answer to the worlds problems as they hoped..I'm not 100% that it's the cause of deformed gaskets.

As well...I changed gaskets recently.. no dexcool at all in the system and they were deforming a little after 1.5 years.

so i've read different things here..

i have an 04 with the L36... does this mean I have an aluminum LIM already or not? If so, does this mean I just need to have the UIM work done (pre-emptively of course)?

i want to get it done before anything happens.

I too have an 04 with L36, and no it does not have aluminum framed LIM gaskets. They have the same junk plastic that causes problems. I changed mine as to avoid future issues.

I wish I knew what my car had for gaskets. I know I got the newer stock upper intake when mine went. And I'm 99% sure they put in the new LIM gaskets with that repair.

But then the engine blew up, probably due to coolant in the oil, so I have no idea what's in the new engine....

I am not aware that any L36 or L67s came from the factory with the aluminum-framed LIM gaskets. To our best collective knowledge these didn't appear on the scene at all until mid 2005.

IMO, always assume that you DON'T have them unless you put them in yourself or specifically had them put in.