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View Full Version : Leaky intake manifold gasket replacement How-to with lots of pics of damage



wkma7six
08-26-07, 01:57 AM
Its not a simple job to do, but it can be done with the proper tools and about a day's worth of work. I did mine about 2 weeks ago and it took a full day. Tear down took me about 1.5 hours. This included cleaning and careful removal of components due to the leak and accumulation of crap around the intake manifold/ head mating area. Both of my gaskets were bad and provided a slow leak when the engine was cold and never leaked when it was up to full operation temperature. Cleaning takes several hours to do as it is not an easy task to keep contaminants and dirt from falling into the valley between the heads. I used a vacuum and a scraper at the same time to evacuate all the debris from the mating areas and the clogged waterports.
Here are the steps broken down if I remember correctly.
-Raise vehicle high enough and drain coolant from entire system. Make sure you don't raise it too high that you cannot access the engine bay, but high enough for you to get under and access the large A/C and power steering bracket. Remove all cooling hoses attached to manifold. No need to remove water pump or EGR valve.
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/dis1.jpg

-Remove all upper intake related parts, hoses, egr bypass tube, and related electrical connections (even the ones that go to the alternator, A/C compressor, ignition modules, and distoributor) attached to intake manifold. If you have a bungee cord handy, wrap it around the main wire loom that crosses over the intake manifold and hook it to the holes/cutouts under the hood's internal bracing. Doing this with the loom simplifies removal and reinstalling manifold if you're doing this by yourself without a helper holding up the crossover wire loom. Then remove the ingition coil/module assembly.
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/dis2.jpg
-Remove the distrubutor and hard fuel lines (relieve the fuel pressure first) attached to fuel distribution block. You should remove the two rear fittings as well that run down to the incoming and return lines.
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/disAC.jpg
-Remove Air conditioning comressor without detaching lines and swing over to side while providing support underneath the compressor. After this remove the two long bolts and nut that hold the aluminum A/C bracket to the block. Next, go under the vehicle and remove the 3 nuts that hold the powersteering pump and bracket to the block. No need to detach the pump from the large aluminum bracket. Then go back up to the top and swing the bracket out of the way in a forward direction. No need to remove, just move it far forward enough to expose the bolt that holds the intake manifold down on the left front corner (driver's side). At this point you should have what appears to be a basic engine with a modern ABS intake plenum sitting on top. No need to remove the upper plenum. I did remove the MAP sensor as it sits a little high. This was done so that I don't break it while flipping the manifold assembly afterwards for cleaning.

wkma7six
08-26-07, 01:58 AM
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/int1.jpg -Now is the time to remove the intake manifold. Use a criss cross pattern to remove the manifold from the block. Start from the outer bolts, then work your way towards the center. On mine, all the bolts were actually loose and some were even finger tight. I guess the gasket compressed so much and detiorated to the point the bolt torque did nothing to hold it in place. There will be some coolant remaining if you didn't drain the radiator completely. Before you take the manifold off, do a thorough cleaning of the area around the intake manifold mating areas next to the heads and block. This ensures you don't have any surprise debris falling into the engine. The manifold will be stuck on due to the RTV that holds the ends down. Carefully pry off and wiggle it loose. At this point you can lift up and remove it. Remember the bungee recommendation? This is where you will appreciate the wire loom not hanging up on the manifold while removing on you own.
Clean up all mating surfaces with a gasket scraper. Make sure RTV is removed from all gasket surfaces. Clean out all coolant passages.
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clog1.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clog2.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clog3.jpg

wkma7six
08-26-07, 01:58 AM
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clog4.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/int2.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/int3.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clogopen1.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clogopen2.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clogclean1.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/clogclean2.jpg
On mine the coolant passages looked like clogged arteries ( passenger rearmost cooling port). Luckily it was just the blockoff at the intake manifold. I guess the leak with small amounts air introduced into the cooling system caused a catalytic reaction and formed hard deposits and buildup at the point of infiltration in the gasket. The driver's side rearmost coolant port even appeared to have coolant mixing with water as there was a small muddy/milky mess. Luckily, there was no oil in the cooling system though.
After cleaning up all mating surfaces on the intake manifold, heads, and block, apply RTV to the front and rear surfaces of the block. Make sure you have enough to compress when the intake manifold is placed on top to form a good seal. I added about 3/16" tall and wide bead. Apply RTV to the topside and bottomside of the new intake gaskets around the coolant passages. Do this sparingly as it does not need much. Just extra insurance incase it reoccurs in the future if the plastic gaskets fail again. Make sure you do not disturb the RTV and carefully place the intake manifold assembly straight down without twisting or rotating it. If you do happen to do this you can ruin the RTV seal and must reapply the RTV again. After the manifold is situated, torque down to manufacture's specs in a series of 3 gradual torque settings from center bolts in a criss cross fashion.

-The rest of reassembly is reverse of removal for the external, and electrical components.
http://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/finish1.jpghttp://img.photobucket.com/albums/v320/wkma7six/S-10%20intake/finish2.jpg

-Flush out the cooling system thoroughly and refill with the proper coolant along with distilled water and make sure you bleed the system properly to avoid getting trapped air in cooling system.
Test drive vehicle and make sure you have no leaks and performance is ok.
*Big tip* Don't wait like I did to do this. All this damage inside was caused by waiting and procrastination for a year! I was lucky it didn't spread through the whole system and remained localized to the intake manifold.
Hope this helps!!
-Walter

Mikz86TA
08-26-07, 02:20 AM
Good write up. Great pics of the guts =) Ohh balance shaft and guides. Sucks it happened to you and it looked like a mess. Looks all better now.

00S104.3
08-26-07, 04:36 AM
Brings back memories of when I did mine. I think mine was dirtier than yours.

http://i18.tinypic.com/54dpqo3.jpg
http://i16.tinypic.com/4zyh69w.jpg
http://i14.tinypic.com/5058c1y.jpg

Slacker1357
08-26-07, 06:47 AM
Looks like the engine was ready to just cease up one day. Good job, I wnder if thats how my 88jimmy died

Tink
08-26-07, 06:09 PM
Great write-up! Hope you don't mind, but I stickied it - thought it should be something that stays near the top...

wkma7six
08-27-07, 12:11 AM
Great write-up! Hope you don't mind, but I stickied it - thought it should be something that stays near the top...

Woohoo!! Got me a sticky after only 10 posts.

Here to help!! There's lots of good info on the site.

texan
12-10-07, 10:20 PM
Ok so it looks like two of yall, have done this work before. So how much to do it to mine, i have almost zero time, and i would be more than willing to help and learn, i have the tools and parts. Any takers? Im in southern cali... Plus when i have tried looking for the leak which occurs about every time i start the truck or fill it with water, it seems to be coming from the middle larger pulley? Now im confused, because i got the gaskets and read this forum and thought it was the intake manifold gasket but cant seem to find exactly where is leaking from. Plus, i have read the forums well about six of them on the ticking noise and gets worse as the rpm's rise. Well, im guessing its a lifter, once again i have no time to tear it all down and replace let alone how to do valve adjustments. Any thoughts or ideas, or preferably help? I dont have the 700 bucks that it will take for labor. P/s i just joined this place today, i just hope yall have some guidance. Thanks again

bespurcell
12-10-07, 10:27 PM
Welcome to the planet. I would help you if I lived closer.

texan
12-10-07, 10:29 PM
Any idea where else the coolant could be leaking from besides the typical intake manifold gasket? Also, how do you tell if which lifter is bad?

LowSDime97
12-28-07, 12:19 AM
wow this looks like so much fun i cant wait until i do mine...ppl were saying its prolly the intake gaskets on my truck, but idk what to do at this point cuz i was wanting to build a V8 but thats gonna cost me so much money that i dont have, and im sure an intake gasket is a lil cheaper than a V8 build

warp9pnt9
01-03-08, 02:27 PM
-Remove Air conditioning comressor without detaching lines and swing over to side while providing support underneath the compressor. After this remove the two long bolts and nut that hold the aluminum A/C bracket to the block. Next, go under the vehicle and remove the 3 nuts that hold the powersteering pump and bracket to the block. No need to detach the pump from the large aluminum bracket. Then go back up to the top and swing the bracket out of the way in a forward direction. No need to remove, just move it far forward enough to expose the bolt that holds the intake manifold down on the left front corner (driver's side).

At this point, I've moved the A/C compressor out of the way, and removed the top 3 things: two bolts and a nut.

Not sure what the three nuts underneath look like, or where to find exactly. Additional picture would be great. I'll take a picture and someone can circle them? ;-) It seems like the only three nuts are behind a pulley, but wasn't anything about a pulley mentioned for this step. Do I need to remove the pulley? Not sure what sort of bolt head is on the pulley. Seems to be a 6-sided indentation, hex wrench or something? What size? Forward or reverse thread?

EDIT: Additional info.

Ok, looking behind the pulley, I saw 4 bolt heads. I don't have a pulley-puller so I used open-ended box wrenches (14 & 15mm), and just barely able to get the wrench on the bolt head in the narrow space behind the pulley. LUCKILY the bolts were all very clean and not rusted or gunked up, so they turned easily with the fingers after loosening. One on the middle-right, one on lower-left just outside the pulley, and two on the middle-left side. Since I was only looking for 3 bolts here, I didn't realize the 4th bolt was holding the bracket. I gently pulled forward and was just barely able to get to the manifold bolt. Just BARELY able to get the manifold out. Really MUST get the extra 1/2-3/4" of clearance that 4th bolt will let me get. It's real tight in there. I'd say do all 4 bolts, so you don't bend or snap the 4th one as you try to get an extra 1/4" clearance by pulling harder.

torskdoc
01-29-08, 11:46 PM
Ok so it looks like two of yall, have done this work before. So how much to do it to mine, i have almost zero time, and i would be more than willing to help and learn, i have the tools and parts. Any takers? Im in southern cali... Plus when i have tried looking for the leak which occurs about every time i start the truck or fill it with water, it seems to be coming from the middle larger pulley? Now im confused, because i got the gaskets and read this forum and thought it was the intake manifold gasket but cant seem to find exactly where is leaking from. Plus, i have read the forums well about six of them on the ticking noise and gets worse as the rpm's rise. Well, im guessing its a lifter, once again i have no time to tear it all down and replace let alone how to do valve adjustments. Any thoughts or ideas, or preferably help? I dont have the 700 bucks that it will take for labor. P/s i just joined this place today, i just hope yall have some guidance. Thanks again


If your leak is coming from the "Middle larger pulley" (this is the one with the fan on it??) then your water pump is leaking. Get an inspection mirror and a flashlight. Put the head of the mirror under and behind the pulley so you can see the bottom 1/2 of the pump and look for a drilled weep hole under the shaft. You will mor than likely see water streaking and some water in the hole. if that's the case, get a water pump. Really easy as it's only 4 bolts on th pump. Same as a SBC. Flush and fill, purge all the air out and keep on trucking.

Larry

'94 Big Blaze
02-17-09, 10:07 AM
sorry to bring back a old thread, but can all this mess show up in the oil ? cause this looks like whats in my oil every time i check it.

warp9pnt9
02-17-09, 10:31 AM
Hey, I'm not a trained mechanic yet, though I am starting my ASE classes this spring and my goal is to be ready for master tech in 2 years. :) I did however rip apart my intake manifold and have it put all back together and no more coolant loss or puddles under my truck.

Mine wasn't so bad that it was in the oil yet, luckily it was mostly leaking out externally through the gasket. If you're losing coolant, and you don't have puddles, drips, or can't see any leaks around the edges of the manifold gasket, AND your oil is looking milky (not sure what that looks like), then it may well be the intake manifold gasket.

From what I understand (of the Dex-Cool coolant, and maybe applies to others), gasket leaks can let air into the coolant system which will cause rust and rot (DexCool + oxygen == corrosive oxidizer, + iron == rust), and clog the coolant system, and could also let that debris flow into the oil stream and get into the cylinders and really then you're screwed, engine rebuild.

Slacker1357
02-17-09, 11:05 AM
Come late spring into summer, when the weather is nice, and the car is on the road, I still plan on taking my Manifold off and cleaning everything.

warp9pnt9
02-17-09, 11:17 AM
Yeah, it's got to be warm enough to have the gasket sealant work right. Not sure what the temperature range is, but I imagine 50-60F would be good.

MiamiZQ8
03-03-09, 05:40 PM
So what is the proper way to retorque your bolts down to? Also, what is the proper ft. lbs. to retorque your bolts down to?

warp9pnt9
03-03-09, 05:49 PM
The torque amount and pattern is in a Chilton's or Haynes book. It may also be on the forum somewhere. I can't remember off the top of my head. I do remember there's 8 bolts, and you can think of them as 4 inner and 4 outer bolts. If I had to take a wild guess I'd probably say hand tighten with fingers just until snug each bolt until all snug, then go through like 2-3 passes, doing one inner and one outer on the opposite side/end, and going around like that, so you're not chasing any loose bolts. Second pass tighten gently with a wrench. Third pass tighten more firm. Maybe fourth pass do the actual torque.

polecat
03-03-09, 05:53 PM
So what is the proper way to retorque your bolts down to? Also, what is the proper ft. lbs. to retorque your bolts down to?

Torque the eight bolts in the correct sequence, three separate times. The first time to 89 inch lbs. The second time to 106 inch lbs. The third time to 132 inch lbs.

The torque sequence is

5 6
2 4
3 1
7 8

jnich12
03-24-09, 02:50 AM
i just joined this forum today (3/23) and was impressed with what i saw (hard to find this kind of detail). with the weather changes in MI (grand rapids) i have experienced a leak of coolant. i dont think its a head gasket because my oil and coolant arent mixing, and no exhaust discoloration. pretty sure i have narrowed it down to the intake manifold (since it is leaking from the engine). i am wondering, though, what will the gasket look like if it is distorted? will it be a pinhole size or crack? anyone?:sonar_125 2002 s10 v6 4.3 (zr2)

warp9pnt9
03-24-09, 07:19 AM
i am wondering, though, what will the gasket look like if it is distorted? will it be a pinhole size or crack? anyone?:sonar_125 2002 s10 v6 4.3 (zr2)

On mine, the visible outside edges of the intake manifold were moist with coolant in a few spots, with coolant dripping down and leaving puddles. The leak was mostly external. Having no prior mechanic experience, I couldn't see any other visible sign that the gasket was bad. Mostly I think it's the silicone bead that breaks down. The leak on mine was mostly from the valley beads where there is no gasket, only the bead. If yours is dry, then maybe it just went the other way and leaked internally? But you said the oil seems to be ok? Wipe down around the edges of the intake manifold gasket and see if moisture returns after each drive to be sure it's not external?

In any case, I think if you're losing coolant, check hoses, radiator, intake manifold gasket. If there's no other external sign, it's got to be an internal leak somewhere, and the intake manifold is high on the list of culprits.

12sws27
03-24-09, 05:55 PM
If you change the Intake gaskets, this is the set to get. FEL-PRO Part # MS98002T.
It's got the upgraded metal frame intake gaskets. It comes with valve cover gaskets and all. The smaller kit doesn't come with the upgraded gaskets. If you get these from http://www.rockauto.com/ and use this code, F3DF7C41D468 . You'll get a 5% discount. It'll end up being $66 and change, shipped. That's $20-$25 cheaper than Advanced or AutoZone. The code expires 5/25/09. Even if you get them from rockauto with out the discount it's cheaper. I just did my intake gaskets :D

jnich12
03-25-09, 02:36 AM
i read on a different thread that one doesnt need to torque the maniflod to the specifications with those, just with the plastic kind so they dont brake. also, how long did it take you to change them out, any hagups?
(S10PLANET.COM (http://www.s10planet.com/forum/index.php) > Mechanical Forums (http://www.s10planet.com/forum/forumdisplay.php?f=162) > Vortec V6 Tech: 4.3L (http://www.s10planet.com/forum/forumdisplay.php?f=13) > Cooling and Heating (http://www.s10planet.com/forum/forumdisplay.php?f=351) go here then down to prostreet94s10's post to eye witness it. could be a dumb A$$ taking a lazy shortcut, or not?

jnich12
03-25-09, 02:43 AM
oops, if you want to find the quote, then after "cooling and heating" go down to "intake maniflod info needed" then to page three then to prostreet94s10.

jnich12
03-25-09, 04:47 PM
so i went to advanced auto today and the plastic gasket set was $40, and the metal was $80. will the plastic get the job done sufficently, or should i dig in my pockets a little deeper and pay double for the metal kind. (both are fel pro) :alc:these smiles remind me that i have tonight off! getting:hammer:

12sws27
03-25-09, 04:57 PM
If you change the Intake gaskets, this is the set to get. FEL-PRO Part # MS98002T.
It's got the upgraded metal frame intake gaskets. It comes with valve cover gaskets and all. The smaller kit doesn't come with the upgraded gaskets. If you get these from http://www.rockauto.com/ and use this code, F3DF7C41D468 . You'll get a 5% discount. It'll end up being $66 and change, shipped. That's $20-$25 cheaper than Advanced or AutoZone. The code expires 5/25/09. Even if you get them from rockauto with out the discount it's cheaper. I just did my intake gaskets :D
^^^^^^^

so i went to advanced auto today and the plastic gasket set was $40, and the metal was $80. will the plastic get the job done sufficently, or should i dig in my pockets a little deeper and pay double for the metal kind. (both are fel pro) :alc:these smiles remind me that i have tonight off! getting:hammer:
Order them from Rockauto for $66.

I did have a hang up. While my truck was sitting and I was waiting for the parts some ass broke into it a stole most of my tools. With some of those tools that were stolen I have a few bolts. So It took me awhile to put it back together :( It shouldn't take you more than5-6 hours I guess. The torque specs Felpros suggests for the metal gasket are no different then whats in the Haynes manual. Well except that Haynes uses in/lbs and felpro uses ft/lbs.

12sws27
03-25-09, 05:04 PM
oops, if you want to find the quote, then after "cooling and heating" go down to "intake maniflod info needed" then to page three then to prostreet94s10.
Don't pay that idiot no attention. Do it the way GM, Haynes and Felpro all suggest.

12sws27
03-25-09, 05:07 PM
Oh wait! I did hear you could get just the intake gaskets alone from the dealer. IIRC it was the permadry's too. I can't remember what they said they cost though. Probably close to what the cheap Felpro kit costs.

Slacker1357
04-04-10, 06:43 PM
I just found this site as well... alot of pics and probably a little overkill

http://www.handymanlyness.com/archives/auto/repair/engine_mech/intake_manifold/GM_truck/gasket_replace_99_Jimmy.html

Jongo88
04-04-10, 07:16 PM
I just found this site as well... alot of pics and probably a little overkill

http://www.handymanlyness.com/archives/auto/repair/engine_mech/intake_manifold/GM_truck/gasket_replace_99_Jimmy.html
Why do all that work and put the same shltty gaskets back on???
He did a lot more than he had too.... Like take off the dissy cap and then after a lot of other stuff he comes back to remove it. Dam.. Just pull it and be done with it...

spideyjected
04-04-10, 07:26 PM
Mine didn't take that long...

Slacker1357
04-04-10, 10:57 PM
Like I said, a little overkill... but tons of info and pics. Useful to me.
as long as he sticks with the green stuff instead dexcrap... he should be fine.
I think I might take a stab at this when the week of nice weather comes along someday. I'll take a couple days off work to work on the truck and relax