Replacing the Intake Manifold Gasket - What a Nightmare!

[RandyatBBY]

Hear is a picture looking up from below drivers side. It is hard to see this is to get a general idea.

this is a close up of the plug


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[RandyatBBY]

It might be easier if I remove the brace. I am going to try that now.

 

[bubinga]

I just want to say thanks ,Gregski, for posting this, I have an FSM but this helps
I have to fix mine got a leak
Question: do you need to remove valve covers or not ??

 

[RandyatBBY]

I just want to say thanks ,Gregski, for posting this, I have an FSM but this helps
I have to fix mine got a leak
Question: do you need to remove valve covers or not ??

Yes you do need to remove one valve coverI had the most trouble getting the fan off. I ended up getting two longer bolts to hold the pulley.

 

[bubinga]

Since I am going to be doing this ,I figured I would add info while in the process.
This is mainly to give Torque Specs

Lower Intake Manifold Bolt ,Torque Specs & Tightening Sequence ,for 99/5.7

First Pass in Sequence
3 N·m
27 lb in

Second Pass in Sequence
12 N·m
106 lb in

Final Pass in Sequence
15 N·m
11 lb ft


------------------------------------------------------------------------

Upper Intake Manifold Stud
First Pass 44 in.lb
Final Pass 89 in.lb



-----------------------------------------------------------------------
Install the power steering bracket onto the stud.
Install the nut onto the stud finger tight.
Install the three bolts finger tight.
Install the two nuts to the back of the power steering pump. Tighten
Tighten the nuts and the bolts to 41 N·m (30 lb ft).
---------------------------------------------------------------

Install the valve rocker arm cover washers and bolts. Tighten
Tighten the bolts to 12 N·m (106 lb in).
-------------------------------------------------------
Install the upper intake manifold studs (1). Tighten
Tighten the upper intake manifold studs on the first pass to 5 N·m (44 lb in).
Tighten the upper intake manifold studs on the second pass to 10 N·m (89 lb in).

If reusing the fasteners, apply threadlock GM P/N United States 12345382, GM P/N Canada 10953489, or equivalent, to the threads of the upper intake manifold attaching studs .
--------------------------------------------------------------------------------
Install the engine coolant thermostat.
Install the water outlet.
Install the water outlet studs. Tighten
Tighten the water outlet studs to 25 N·m (18 lb ft).
---------------------------------------------------------------
Install a NEW throttle body gasket into the groove in the upper intake manifold.
Install the throttle body onto the upper intake manifold.
If reusing the fasteners, apply threadlock GM P/N United States 12345382, GM P/N Canada 10953489, or equivalent, to the threads of the throttle body attaching studs.
Install the throttle body attaching studs. Tighten
Tighten the throttle body attaching studs to 9 N·m (80 lb in).

------------------------------------------------------------------------------
Install the accelerator control bracket, the bolt, and the nut. Tighten
Tighten the accelerator control bracket bolt and the nut to 12 N·m (106 lb in).
-----------------------------------------------------------------------------

Install the distributor mounting clamp bolt. Tighten
Tighten the distributor clamp bolt to 25 N·m (18 lb ft).
---------------------------------------------------------------------

Tighten distributor cap screws.to 2.4 N·m (21 lb in).

 

[bubinga]

Yes you do need to remove one valve coverI had the most trouble getting the fan off. I ended up getting two longer bolts to hold the pulley.

Keep in mind I haven't done this yet but , why is it necessary to remove the fan??

 

[RandyatBBY]

Keep in mind I haven't done this yet but , why is it necessary to remove the fan??

I am assuming you have original water pump like I did and need to replace it.

It is a good time with all the stuff out of the way good insurance and drains the block of antifreeze necessary to remove the intake.

 

[COLVTAHOE]

Hello Everyone.

I'm new as of about 20 minutes ago, and I can admit I NEED HELP!!! haha. I too have the same leak and it seems to be coming from the back. After investigating further, I notice that it could be anywhere along that whole side.

I thank you all for the VERY useful information. I was dreading having to pull the entire engine. I am 99.9% sure this is the cause of my leak, as well.

Can anyone please recommend any good service manuals for this model. More specifically the '99 Tahoe. I understand they are the same for the most part. But I need every advantage I can get at this point. I am in a race to beat the freezing temperatures of late fall/winter.

Also, can anyone provide an overall cost I am looking at to repair this? I am pretty savvy with fixing my truck (thanks to my old man), so thankfully I can perform the labor myself. Can anyone provide links to the requires gaskets, recommend any upgrades or coupon codes for websites?

One thing to bare in mind, i'm a broke and back in college student working full time for little pay. Every little discount (but quality matters) will help me out. As well as anymore pictures and possible walk-through to save myself some time.

Thank you advance gentleman, and ?ladies? perhaps? Your help to this point has been tremendous and for that alone I thank you already.

 

[bubinga]

Don;t know if U repaird this yet, I haven't been here in awhile.
I have a 99 Hoe

This is a manual I bought on DVD,from ebay for 25 bucks, it has the same info as the 4, big paper books and more.
Works GREAT,Great seller
Every one should have one of these, you can not go wrong for the price
The seller has many models and makes.

CHEVROLET TAHOE FACTORY SERVICE REPAIR MANUAL 1998 1999 2000 98 99 00

http://www.ebay.com/itm/CHEVROLET-TA...item337c131b4f

Cost me about 75 bucks,for parts, from Advance Auto ,search on line for Advance Auto discount codes,buy on line pick up at store,or have parts shipped.
Or get parts from Amazon,

http://api.viglink.com/api/click?fo.../B000CH0C0Y/&jsonp=vglnk_jsonp_13522789861317

http://api.viglink.com/api/click?fo...p/B0039SOMUE&jsonp=vglnk_jsonp_13522790096578

I also got the other valve cover gasket.
http://www.amazon.com/Fel-Pro-VS50293R-Valve-Cover-Set/dp/B000C2GIGQ/ref=pd_sim_auto_3

 

[sphillips]

Just finished my intake manifold project yesterday, all is well. Used all of the gaskets in the FelPro set, except for two small o-rings, which I couldnt figure out where they go. They werent the fuel lines going to the upper induction manifold, too small. Time consuming but very doable.

 

[socalTizoe]

Just finished Manifold gasket

I scoured the web for details on how to do this job, including this thread, which helped a lot at least to get the courage to dive in.. I'm not mechanic and I've never dug this deep into the engine, but i had all the tools i needed from repairs done in the past (alternator, water pump, etc..) and i agree.. it's not difficult but there's a lot to remove.. labeling everything was a huge help. and there are a lot of videos and pictures out there, this post helped a lot:

http://www.d-tips.com/general/articles/article.aspx?id=11

My Symptoms:
I was missing coolant but had no leaks.. i found coolant in my oil during the last oil change, radiator did not seem to have any oil discoloration (recent flush and no oil in there either).. i had been losing coolant noticeably for about 3k miles.. I developed a knock on startup which went away after about 2 minutes of warm up. I thought initially it was my head gasket, found out the stock manifold gaskets are junk

Just to help out anyone attempting this repair, here are some notes from my adventure.. I have a '99 tahoe LT 4x4 103k

-You dont need to remove the alternator

-I did not remove the upper intake

-You can slide the AC compressor bracket forward without removing the Power Steering pulley, there is a screw about 1 inch to the right and about 6 inches back from the lower left bracket screw, i think its 14mm.. but i was able to remove it with an extension on the ratchet. wasnt hard, but was hidden

-I could not remove the fan, but removed the upper shroud.. it required a wrench bigger than anything i had, i've also seen some serious struggles removing it.. so i just removed the screws to give me some space (after if realized that the screws didnt release the fan), this just helped get to the AC screws really.. so its not necessary

-I removed both valve covers and replaced the gaskets since I was there.. found some "milkshake" froth in one of them and cleaned them up, this made getting the manifold out easier as well

-I marked each connector i disconnected with a whiteout marker

-you dont need to remove the rear wiring harness (as noted in the article above) which is on the passenger side of the engine, you can bend it back (carefully) 1st, but it will need to be loosened in order to get the manifold back on cleanly.. there was a ground wire attached on mine (it broke and i'm not sure what it does, thoughts?)

-clean the surfaces very well, i applied a little bit of "Grey" to the ports on the manifold which were corroded, and around the ports which had "pitting" on the engine, i've read different feelings on that subject.. but i went for it

-Pour a bunch of oil down the valley after the cleaning and replace the oil before the 1st start

-flushed coolant by removing the lower hose after the reassembly

-removed the oil after reassembly before the 1st start

-drove it lightly about 50 miles and performed engine flush and replaced oil and filter (30% lucas to be safe)

-so far so good, I dont seem to be losing coolant and the truck runs just like it did before the change (very nicely)

so thanks for posting this info, and hopefully someone will find this additional info helpful. I was quoted $800 in labor for the job, and seeing I dont have $800 lying around, the repair has been well worth it..

:smokin:

 

[RandyatBBY]

I scoured the web for details on how to do this job, including this thread, which helped a lot at least to get the courage to dive in.. I'm not mechanic and I've never dug this deep into the engine, but i had all the tools i needed from repairs done in the past (alternator, water pump, etc..) and i agree.. it's not difficult but there's a lot to remove.. labeling everything was a huge help. and there are a lot of videos and pictures out there, this post helped a lot:

http://www.d-tips.com/general/articles/article.aspx?id=11

My Symptoms:
I was missing coolant but had no leaks.. i found coolant in my oil during the last oil change, radiator did not seem to have any oil discoloration (recent flush and no oil in there either).. i had been losing coolant noticeably for about 3k miles.. I developed a knock on startup which went away after about 2 minutes of warm up. I thought initially it was my head gasket, found out the stock manifold gaskets are junk

Just to help out anyone attempting this repair, here are some notes from my adventure.. I have a '99 tahoe LT 4x4 103k

-You dont need to remove the alternator

-I did not remove the upper intake

-You can slide the AC compressor bracket forward without removing the Power Steering pulley, there is a screw about 1 inch to the right and about 6 inches back from the lower left bracket screw, i think its 14mm.. but i was able to remove it with an extension on the ratchet. wasnt hard, but was hidden

-I could not remove the fan, but removed the upper shroud.. it required a wrench bigger than anything i had, i've also seen some serious struggles removing it.. so i just removed the screws to give me some space (after if realized that the screws didnt release the fan), this just helped get to the AC screws really.. so its not necessary

-I removed both valve covers and replaced the gaskets since I was there.. found some "milkshake" froth in one of them and cleaned them up, this made getting the manifold out easier as well

-I marked each connector i disconnected with a whiteout marker

-you dont need to remove the rear wiring harness (as noted in the article above) which is on the passenger side of the engine, you can bend it back (carefully) 1st, but it will need to be loosened in order to get the manifold back on cleanly.. there was a ground wire attached on mine (it broke and i'm not sure what it does, thoughts?)

-clean the surfaces very well, i applied a little bit of "Grey" to the ports on the manifold which were corroded, and around the ports which had "pitting" on the engine, i've read different feelings on that subject.. but i went for it

-Pour a bunch of oil down the valley after the cleaning and replace the oil before the 1st start

-flushed coolant by removing the lower hose after the reassembly

-removed the oil after reassembly before the 1st start

-drove it lightly about 50 miles and performed engine flush and replaced oil and filter (30% lucas to be safe)

-so far so good, I dont seem to be losing coolant and the truck runs just like it did before the change (very nicely)

so thanks for posting this info, and hopefully someone will find this additional info helpful. I was quoted $800 in labor for the job, and seeing I dont have $800 lying around, the repair has been well worth it..

:smokin:

It could have been a head gasket leak from your symptoms did you do a compression check?

 

[socalTizoe]

hopefully not the head gasket

I did not do a compression check because i dont have the tools, but the manifold gasket was destroyed which gave me reason to believe that it was the culprit.. if I continue to lose coolant, i will assume it's the head gasket and take it to the mechanic when i have the funds.. if i dont lose anymore coolant i'll assume the problem is fixed.. thanks for the reply..

 

[lllloyd1]

I did this same job a year ago wish I had read your post, I had to get it timed after I was done. My marks came off and as you know that was that. Also now I have to either replace the Lower or figure out how to re-tap the coolant quick disconnect hole. And that darn one screw is a bear to remove. Thanks of all the great info. by the I took pictures of were everything went, a live saver for sure. Have a great day Leonard

 

[miuwu208]

Inrake Manifold

I am in the middle of the same project your thread is helping. I am stuck on trying to drain the cooling system. I was told that the bolt on the bottom of the block if removed will drain the system but I can not get a good grip in it. I will get a picture of it and post it.

Loosen the knock sensor under the passenger side and drain the block, works great when doing a full flush also JUST MY .2 CENTS

 

[4x4Blazer]

When draining coolant from an engine, I have an old shop vac I use, just suck out the coolant from the radiator at the rad cap neck, then remove t-stat and housing and let it suck out the rest of the coolant from the intake T-stat hole. Works awesome, then no coolant leaks in the lifter valley..

 

[lesterl]

Nice....

 

[FD611V]

Have '96 Tahoe with the 5.7 V8. I also had a coolant leak at the left front on the intake manifold. It wasn't bad, but it also wasn't good to have coolant leaking into the crankcase, which would start bearing wear. My oil pressure when I bought the Tahoe new the oil pressure at start up would be around 60 psi, and settle at 50psi at hot. With the mileage at 129,500 miles (10/2012 year), my oil pressure was 55psi cold, and settle about 43psi when hot. I knew there was some wear on the crankshaft bearing and decided to take on the task of replacing the manifold intake gasket. I did basic the same as most that tackle this job, and few hours of examine what had to be done....removing all the wires and marking/labeling each one. I didn't remove the powering steering pump, just went under and loosing the bolt and slid the pump forward enough to get to the front left side manifold bolt.
I did something that most probably wouldn't do... remove the distributor. I found it was better to remove the distributor to ease the effort in removing the manifold. But, I did something different, marking the distributor in four places so I wouldn't have any problem when re-installing it, knowing if it did it wrong when installing the distributor, I would have to have the engine scanned.
At the base of the distributor I taken a small chisel and made marks both on the manifold and distributor base. Also when I removed the distributor cap, I made three marks...one with the rotor tip to the distributor housing, another on the opposite side, when you remove the distributor it will rotate some 5 degress counter-clockwise and you have to make another mark on the distributor housing there. When you install the distributor you have to make sure it goes back in the same way it was removed. When I finished all as some listed....filling the radiator, changing the oil, etc. I started the engine... Great!!! no check engine light lit up. The engine ran fine....no leaks appeared. I drove the Tahoe some 20 miles and here it is one year later and no leaks or adding any coolant to the radiator.
All is well.

 

[lesterl]

how the he11 would you remove the manifold to do the gaskets without removing the distributor? AFAIK you have to remove it......

 

[laredo1307]

Since I've had my Tahoe the last 4yrs I wonder how it never overheated but yet my reservoir was always dry. My leak must be very small. I've also heard the dreading knocking sound (only under load) from time to time but I have to admit that it's not as bad since I replaced my exhaust and did a tune-up. Somehow this is the first time I've stumble upon this issue. I knew there was issues with Dexcool for other reasons but it looks like whoever had the truck before me had replaced the coolant with something else. They may have even done the manifold gasket repair before but I do not see anything in the records that came with the truck. I'm definitely a "wrencher" by nature so I have no problem tackling this project. But, this thread definitely takes all the guessing out of the way on how to go about everything. I now know what my 1st project will be for the new year.