98 3.8L upper intake designed to fail

recently my daughters intake manifold required replacement because the plastic upper intake manifold cracked at the EGR port...

this is another example of poor quality , and a designed to fail position that GM has been doing for years...

for GM it's 100years of existance soon going to be RIP...

if you experience this ,,,basicly exhaust gases/noise exits the air intake ...also the MAF will show a bad reading ....

I don't know here, I just did my daughter's 98 LTZ, 220k miles, cost me 150 dollars what's the big deal about this after 11 years? Ford has had their issues with this cracking manifold deal although only vacuum leaks are created.

I don't know here, I just did my daughter's 98 LTZ, 220k miles, cost me 150 dollars what's the big deal about this after 11 years? Ford has had their issues with this cracking manifold deal although only vacuum leaks are created.

this problem has been around for a long time and she was fortuate to get this amount of useage before it cracked...this is true...

still it is a failed design...and they should have used a different solution..

point here is if you consider this vehicle this is something that IS gonna fail...no way around it...

cost me 150 dollars what's the big deal about this

Sure it would cost you and I $150 because we can do the work ourselves.
But what about the other people who have to pay $700 - $1000 for this repair. Just a big money generator for the dealer and the repair shops.
I have read many posts about this problem on the GM 3.8's and I believe there is a class action suit pending.
I try real hard to continue to like GM products but when you hear about all the horror stories about quality issues it make me wonder. :confused:

cmon dude, don't blame GM for having a minor problem on an 11 year old car.

cmon dude, don't blame GM for having a minor problem on an 11 year old car.

You call that a minor repair? :screwy:

My problem with GM on this issue is that they misled the public and did not take responsibility for their design flaw.

Everything more or less is gonna break at some point..

I still love my old Chevys :cool:

Al :smokin:

They surrounded the egr inlet to the intake with plastic. On top of that, just on the other side of the plastic is coolant. So, after the intake cracks and leaks, it leaks coolant into the intake which can hydro lock the cylinders. I have replaced dozens of these intakes and I have yet to see any sustained damage other than having to replace the spark plugs on a few of them. Every car manufacturer has poor judgement and stupid design flaws. Whether or not they fix the problem in subsequent years really shows how much they want to improve the product. The 3.8L is one of the best engines that GM ever designed and a few minor problems would not ever deter me from recommending someone buy a car with one in it. The 3.1/3.4 and all subsequent engines of the same design are probably one of the worst GM has ever produced. I cringe when people tell me they bought a car with one in it.

Agreed! 3.8 are pretty tough.

We replace a lot of those with the aftermarket plenums. Supposedly they are reinforced a little better in that area?

[quote=RahX;5932965] have replaced dozens of these intakes and I have yet to see any sustained damage other than having to replace the spark plugs on a few of them. quote]


the plugs required replacement because the MAP sensor was commanding the pcm/computer to inject max fuel into the cylinders because of the excessive intake manifold pressure..

the plugs where full of fuel....
the reason I have brought this out here is,, if the upper/lower intake manifold gaskets need replacing for your safety replace the upper intake....
if this blows on the hyway this could be dangerous...

1. GM's BEST motor ever is prolly the 3.8/ 3.8sc., the only competion here would be a clasic small block imo.
2. GM is suffering because people want a cool looking car that will last for 200k miles. They dont want a plastic car with a shitty motor that you can bet will need work in 5 yrs.
3. Yeah true all cars have problems, but GM isnt allowed to make junky cars, only everyone else is.
4. And yeah maybe it is designed to fail, why else would you go to the dealership? They need a chance to sell you another junk car. They know that people dont want to rip into theyre cars engine and fix it themselves.

I've never had one blow out. They seep forever and 9/10 they fill the intake with coolant after you shut the engine off and you can't get it started the next morning because it is hydro-locked. The plugs i've changed probably needed to be changed anyway but they were nice and orange thanks to the dex cool.

1. GM's BEST motor ever is prolly the 3.8/ 3.8sc., the only competion here would be a clasic small block imo.
2. GM is suffering because people want a cool looking car that will last for 200k miles. They dont want a plastic car with a shitty motor that you can bet will need work in 5 yrs.
3. Yeah true all cars have problems, but GM isnt allowed to make junky cars, only everyone else is.
4. And yeah maybe it is designed to fail, why else would you go to the dealership? They need a chance to sell you another junk car. They know that people dont want to rip into theyre cars engine and fix it themselves.

all vehicles have defects....this is true..
the reason GM is going bankrupt, is because of how you ,,,,the vehicle owner , are treated when brought in for a warrantee repair....

dealerships are forcing the tech's to make half azz repairs , instead of properly repairing the vehicle in hopes that soon you will be beyond the warrantee period....

you think GM is so great ,,,,,,the stock price is less than two bucks buy a few hundred shares.....

you think GM is so great ,,,,,,the stock price is less than two bucks buy a few hundred shares.....


Even at that price you will probably lose your shirt. Even with the stimulus injection of cash for GM, I don't see how the company can survive doing business as usual. I think the cash is really mean't to save jobs.
Pumping cash into GM is like putting a band aid on the hull of the Titanic to keep it from sinking, it ain't going to work. Maybe temporarily.:headshake

I hope GM survives, I want to see what the next Z-28 Camaro will be like.

I hope GM survives, I want to see what the next Z-28 Camaro will be like.


I own a 1984 camaro berlinetta , and was interested in this new camaro...saw on tv the testing and details....as displayed it looks good.

what happens after the bean counters f it up remains to be seen....IF GM lives ....

I have a 98 Montecarlo Z34 with this motor.. So far I havent seen this problem.. it has 95K miles.. How do I know this problem is starting to occur. Ive been watching the overflow bottle. :uhoh:

What should I watch out for?

I have a 98 Montecarlo Z34 with this motor.. So far I havent seen this problem.. it has 95K miles.. How do I know this problem is starting to occur. Ive been watching the overflow bottle. :uhoh:

What should I watch out for?

You must be one of the lucky ones.
From what I have read here, you should change the coolant at LEAST EVERY 3 years.
In the mean time, keep an eye on the coolant level..

Al :smokin:

I have a 98 Montecarlo Z34 with this motor.. So far I havent seen this problem.. it has 95K miles.. How do I know this problem is starting to occur. Ive been watching the overflow bottle. :uhoh:

What should I watch out for?

the upper intake manifold on my daughters vehicle had no coolant issues...this is a sudden failure with NO warning....there was a sudden pop and then the engine had no power ...eventually the plugs got flooded with fuel as the MAP signal was causing the excess fuel due to the incorrect intake pressures...

this is a crack that forms as the EGR heat causes the poorly designed plastic to fail...

the reason I posted this is ,,,,,If you do have a bad intake gasket problem upper/lower replace the upper intake as well....because its gonna fail...

this vehicle has never had any gasket problems ....I maintained the coolant system and their is no corrosion.....

on your vehicle since it is now old the damage is done,,, if you have not used distilled water and kept the ratio of dexcool to water correct....I use 66% dexcool to 33% distilled water....

i have a 99 monte z34 with 300,000 kms& i have never had a problem with the upper intake at all. but the brakes are pretty aweful if you ask me.

i have a 99 monte z34 with 300,000 kms& i have never had a problem with the upper intake at all. but the brakes are pretty aweful if you ask me.
I am looking to buy a 98 Z34, could you elaborate on your brake issues?? Thanks

The rotors tend to worp & bend very easily which makes the pads wear quick. Take my advice don`t go cheap when it comes to brake cuz they won`t last. When you do upgrade the brake you will not have any problems.

The rotors tend to worp & bend very easily which makes the pads wear quick. Take my advice don`t go cheap when it comes to brake cuz they won`t last. When you do upgrade the brake you will not have any problems.

never had issues with the rotors heat damaged ...replaced the rotors all at 100,ooomi all rusted ...original ones ...installed advanced auto rotors/bendix OEM grade pads no problems at all ..2+ years now ..

all parts have lifetime warrantee...any failure just bring in the pads/rotors and no cost for you !