95_Z-28_runner

is this a common problem on 1994-97 cars? beacuse my car seems to be leaking oil from the rear of my intake. i looked and it is a tech service bullten for this problem do to the ATV sealent. so anyone let me know just curious thanks.

defaultexistence

iTrader: (11)

Yes, Absolutely

Puck

iTrader: (17)

Common problem, but easy fix.

Pick up the intake manifold gasket set from your local auto parts store. They are just the side pieces, no material for the "China Walls". Ignore the cheap RTV they come with, and use "The Right Stuff" RTV on the seams. I like to put down a decent size bead, let it sit for a few minutes to get a thin film, then apply the intake and TQ it down in sequence.

Paul Bell

iTrader: (9)

The heat from the EQR tube is why the rear seal goes bad. When I had the '94, I wrapped the tube with some of that shiny heat shielding stuff.

LT1FirebirdSLP

iTrader: (2)

You could always remove your EGR and block it off! Has to be changed in your tune too.

SS RRR

iTrader: (2)

Total myth that was regurgitated by Ken Collings years ago from some other know nothings. They claimed the manifold would "raise" or "warp" off the block as well as sealant being "burned off..." It's crap. It has nothing to do with the EGR tube nor should you need to use heat shielding. This was explored in great detail when there was no known explanation. Many who delved into this issue, including GM mechanics pretty much all stated the same thing- the problem originates from a lack of sealant and/or poor torquing sequence from owner or factory. GM intake gaskets also have a shrinking issue where once heat cycled, they will shrink and intake bolts will become lose.
Because the clearance between the manifold and block is so great there is very little margin for error when trying to achieve a perfect seal that will last.
The steps are as follows:

Scrape all gasket material and sealant off. Clean the living **** out of the mating surfaces of the manifold with carb cleaner or brake cleaner. One can argue about brake cleaner leaving a film or whatever, but it works. Pick your poison.

Apply a generous/continuous bead of sealant on front and back. Don't use the applicator supplied. Just poke the tube and apply. Use either GM's Right Stuff, Permatex Ultra black or Ultra Copper.

You can let the bead sit if you'd like. Your choice.

Set manifold straight down. Don't set it down and then move it. Again, because there is such a dependency on the sealant acting as an extension of the block it's best not to disturb the contact surface. Use a couple of cut up pencils in the cylinder head bolt holes for dowels to aid in setting the manifold perfect.

Before doing any of this make sure you get any towels/shop rags out of the oil valley and cylinder head intake ports.

Torque manifold in sequence using two passes. One at 15ft.lbs. and the next at 35ft.lbs.

Wait at least 12 hours before starting. Again, the bead is thick because of the great clearance. Give it time to cure.

After a weeks worth of heat cycles, check the torque of the manifold bolts.

BOLO

iTrader: (40)

Yes, the LT1 intake infamous leak. I'm sure anyone who have owned an LT1 have experienced this leak at the back of the intake. The "Right Stuff" sealant have worked for me without any problem.

ZFreie

Sure is, first time I tried fixing it I didnt use enough rtv. Make sure you lay a generous bead on the back. second time around I used more and no leaks.

97FormulaWS-6

iTrader: (1)

Be sure to check your oil pressure sender while you're in there... I fought this leak for years before I found the sender had a TINY crack in it that was leaking oil down the back of the motor.

Rob94hawk

iTrader: (1)

How far up the cylinder heads do you apply the sealant? Over the tabs on the gaskets?

AND, are the gaskets a one shot use only of you already torqued down the manifold?

ZFreie

I put a small amount under and over the tabs. No idea on the gaskets, I replaced them cause I had another set. For the 20 bucks for the gasket set I figured this way i def wont have issues. So far so good lol

SS RRR

iTrader: (2)

Either just to the tabs or over. Doesn't matter.

Yes they are one use only.

Paul Bell

iTrader: (9)

SS RRR, I'm going to counter you here sir.

On my 1994 Formula, the gasket material was without a doubt damaged from the heat from the EGR tube. It had physical signs of high temperature and what was left of the sealant/gasket was hardened from the heat. The damage was centered exactly where the EGR tube was. The cause of the leak was obvious and without a doubt the heat from the EGR tube.

While the oil leak issue may also be caused by other reasons as you say, EGR tube heat can also be the cause and should not be totally ruled out.

SS RRR

iTrader: (2)

I would say before believing the EGR is at fault, other things should be explored.

shbox

The heat from the EGR tube might have affected the original sealant, but it does not seem to affect the newer stuff. I mean, I've had no leaks with the manifold being on there at least twice as long as the factory install and still in the presence of the EGR tube heat. I think if GM had done the sealant right from the factory, the EGR tube heat would not have been suspected as being a factor.

ahritchie

iTrader: (1)

Whatever causes the intake leak (poor design, shitty sealant, heat, ect) it happens to 90% of LT1s once you gets some miles on them. Not unlike the joys of replacing optisparks well before their supposed 100K lifetime. Just something to get used to with the old LT1.

Paul Bell

iTrader: (9)

Agreed!

leadfoot4

iTrader: (1)

I don't know, "shbox", the OE sealant lasted 3 years, and it seems like I have to reseal the intake on my car every 4 years, like clockwork... I'm the original owner, had the car for 16 years.

Paul Bell

iTrader: (9)

Hey, I'm just curious. Exactly what area of the gasket was the worst?

shbox

Last time mine was opened up was 2003. Ultra Copper used. No leaks today.