LOWER intake manifold gasket on 3400s?

[madmac9]

I am brand new to the GA world as you can see by my several posts. I wanted to know if the intake problem happens to the 3400s.

[99GrandAMSE]

Sorry to say ... YES :( it is quite common

[USMCspy]

How do you tell if there is a leak?

[Themeneea]

your coolant will start to go down and there is no leak. i check mine once a week

[madmac9]

What is the best way to prevent this problem from happening?

[99GrandAMSE]

Originally posted by madmac9
What is the best way to prevent this problem from happening?

... I don't believe there is an 'actual' way to prevent it from happening; however, there is a great deal of 'theory' around about it ... the first thing some say is to remove the Dexcool and replace it with the 'green stuff' but I am not convinced of this fact yet.

[Old Guy]

Originally posted by 99grandamse
... I don't believe there is an 'actual' way to prevent it from happening; however, there is a great deal of 'theory' around about it ... the first thing some say is to remove the Dexcool and replace it with the 'green stuff' but I am not convinced of this fact yet.

I agree....I really doubt that changing to the "green stuff" will help much. I'm hoping that keeping the car running a little cooler (180 degree thermostat and watching the temp so you can manually turn on the fans) will delay having to replace the gasket. I just think we'll have to live with the problem though :(

[mikem220153]

My understanding is that there has been a problem with the design of he oem gasket. I also understand that companies like Fel Pro redesigned the gasket to help with that problem. That is why I specified the Fel Pro gasket set at the parts store, when I replaced my gasket.

Oh yeah, these gaskets can leak externally. It's a pretty good bet that when they do, they will start leaking internally as well.

[99GrandAMSE]

Originally posted by mikem220153
My understanding is that there has been a problem with the design of he oem gasket ...

:agree:

[madmac9]

Originally posted by mikem220153
My understanding is that there has been a problem with the design of he oem gasket. I also understand that companies like Fel Pro redesigned the gasket to help with that problem. That is why I specified the Fel Pro gasket set at the parts store, when I replaced my gasket.

Oh yeah, these gaskets can leak externally. It's a pretty good bet that when they do, they will start leaking internally as well.

So you replaced them before anything happened right? How much were they? I see you live in phoenix so maybe you could help me out with this thing.:D

[Old Guy]

Originally posted by madmac9
So you replaced them before anything happened right? How much were they? I see you live in phoenix so maybe you could help me out with this thing.:D

There ya go Mike!!! You can become the #1 GA mechanic in Phoenix!!! Heard you're good at Struts and brake jobs too.

Want to fly to Ohio and take care of mine when they go? I'll even cook dinner.... :D

[madmac9]

Hell I would pay you and cook you dinner if you would become my mechanic on my car! heh

[mikem220153]

madmac9,

Does your car show any signs of leaking from the intake manifold gasket? Like water mysteriously disappearing with no sign of a leak? or coolant on the front or back of the motor?

Here are a couple of pics the problem areas on the V6:

[mikem220153]

Here is another:

[madmac9]

Originally posted by mikem220153
madmac9,

Does your car show any signs of leaking from the intake manifold gasket? Like water mysteriously disappearing with no sign of a leak? or coolant on the front or back of the motor?

Here are a couple of pics the problem areas on the V6:

No no no no, I just bought my car and had been reading about this problem and wanted to know about it. I have none of these problems. But at what miles typicaly does this happen at?

[mikem220153]

Well, that is hard to say. I have seen it happen to some as early as 40K and mine happend around 118K so milage doesn't seem to be a factor. About the only thing I can recommend is to keep your engine and cooling system properly serviced, and check for signs of this problem as a matter of routine, and fix it at the 1st sign of leakage or vanishing coolant.

[usranger1]

I had my Intake Gasket replaced in Jan 2003 and this is Aug 2003 and it is leaking again. It is leaking in the same spot as last time. Both of my leaks have been external leaks, you can see the coolant and/or oil coming down the side of the motor just under the throttle body. I have emailed GM several times signed petitions and the whole nine yards. I guess this is just a problem that me have to get use to.

[99GrandAMSE]

... if your repair only lasted 8 months then I would suspect the trouble now is due to 'faulty' workmanship as opposed to another gasket problem; although, I know this has happened before :(

[usranger1]

Well, I took my car in today and they told me that it was not leaking. I showed them where the oil and/or coolant was running down the block. So they added dye to the system and told me to come back in a week.

[mikem220153]

Dye?? Well, that is a 1st. for me. I have never heard of using any kind of dye to locate an oil or coolant leak. Where did they put the dye in at? The engine or cooling system? If your's is leaking under the throttle body, then they probably didn't get the upper flange area of the block sealed right. That area is sealed using black RTV sealant. My guess is that you definitely have a workmanship warenty issue here.

[Themeneea]

Dye?? Well, that is a 1st. for me. I have never heard of using any kind of dye to locate an oil or coolant leak. Where did they put the dye in at? The engine or cooling system? If your's is leaking under the throttle body, then they probably didn't get the upper flange area of the block sealed right. That area is sealed using black RTV sealant. My guess is that you definitely have a workmanship warenty issue here.

i have heard of using dye and a black light to find oil leaks.

[HeyDace]

If the Tech didn't screw up assembling the intake than its possible that the intake is warped. Also why wait a week for the dye to circulate? I use it constantly and within a few minutes of Idleing it will show right up.

[Old Guy]

Originally posted by HeyDace
If the Tech didn't screw up assembling the intake than its possible that the intake is warped.

You beat me to it.......sounds like a warped intake to me. I'm sure most of us "older" guys have had problems with warped heads which has similar symtoms.

[usranger1]

They told me that they put the dye in my coolant
tank. I guess they are trying to see where the coolant
is coing from. This is a first for me also.

[akabatman2]

Oh crap. Now I am worried.

I just went out to the garage and looked at my car's engine, I have what looks like oil seepage in the 2 area's marked with green rectangles(In mikem220153's pic). The seepage looks more prominent under the throttle body than it does on the Serpentine belt side of the engine.
I changed the oil 2 weekends ago and I just checked the oil level and it looks good. I don't know how to tell if there is coolant in the oil seepage. It just looks like oil to me. There is no residue on the oil fill cap, oil is as clean as the day I changed it.

Should I go to the dealer and tell them to fix my intake manifold or am I just worried.

I noticed that the coolant overflow is lower than the "Full Cold" mark, but it's been that way since I bought it 2 months ago, I think when they cleaned it out they just didn't fill it all the way.

What are your expert opinions?

Thanks.... :bravo:

[rixGAphx]

Keep an eye on things, but there's no need to go looking for trouble.

1. *Most* of the LIM gasket problems were solved before your engine was built.

2. The main problem of LIM gasket failure is in the coolant passages from the head to the LIM. If this leaks, two things happen:
a. You loose coolant, even catastrophically all over the road.
b. Coolant gets in the oil, creates a sludge tan frothy milkshake, and the bearings are ruined by subsequent poor lubrication.

IMO, you are in no danger of LIM gasket failure.

3. IF you have a little oil staining at the front and rear (mike's 'green boxes'), that is NOT an ominous sign of LIM gasket failure.
True, no oil would be better.
But there is no pressurized oil as any part of the LIM, so you aren't in danger of losing oil pressure.
My *guess* is that there is some condensation of oil vapor on the underside of the LIM itself, and this condensed oil is dribbling out thru a tiny hole in the sealant that seals the LIM to the iron web of the block that crosses the V.
To verify, apply some spray engine cleaner to the dirty areas and then water-spray the engine clean.
Look for leakage onto the clean metal during the next week.

Also, verify that the PCV valve and air inlet are working properly. Nothing will blow oil vapor OUT of an engine's crankcase and cam galley faster than a plugged PCV system.

I would not have been driving for 2 months with the coolant below the 'Cold Full' mark.
Pour in a couple cupfuls of purified water to bring it to 'full', then monitor the level from there.

I hope you never ever experience coolant-in-the-crankcase, but if you do, you will know it.
Oil and water don't mix. Under normal conditions.
But if you heat them to the oil's temperature (about 250*F), and mix them in the rotating gears of the oil pump, then push them thru small passages at 40-60 psi, they will homogenize just like cream and milk.
Initially the mixture looks like BeeBee-sized oily bubbles on tanish-white liquidy oil. With a little more homogenizing, it looks just like a thin mocha milkshake.
But doesn't lubricate as well :eek:

Good luck.
-Rick

[RocketFast321]

I keep an eye on our malibu it has a external leak under the intake pipe. But it only leaks in the winter. Last winter it leak like crazy. Now that it started getting cold the leak came back (weird)

[akabatman2]

rixGAphx & RocketFast321,
Thanks for posing back.

Rix, When I first bought the car used, it had brown sludge in the overflow. It was pasty and brown, I could scoop some out with my finger. I told the dealership to have the system flushed or I wouldn't buy it. I haven't seen any sludge in there for the past two months.

Yes, the oil looks like it is leaking out of where the RTV glue is at the V area where the LIM connects to the block. Will this cause a problem? Should I have this fixed, from what you are saying is, it's not a problem. I will do as you suggested, I'll get some engine cleaner and spray it on and watch it and let you know in the next couple weeks.

Does anyone have a picture they could post here of where the PCV value is on this engine? I just bought the car an I am not familiar with where things are yet.

Thanks again guys. :bravo:

[rixGAphx]

Originally posted by akabatman2
Does anyone have a picture they could post here of where the PCV value is on this engine? I just bought the car an I am not familiar with where things are yet.
Sorry, I don't have a picture.

The PCV valve is on the valve cover, with a hose going to the intake manifold.
The PCV system sucks oily air out of the crankcase, cam gallery, and valvecover space and sends them into the intake for burning in the cylinder.
When there is no vacuum (engine is off), the little stopper in the PCV valveseals the opening to prevent oily vapors from escaping.

You really need to get a Haynes or Chilton's manual for this vehicle. It will really help, and is well-worth the ~$12.

Good luck.
-Rick