lower intake manifold gasket in progress!!!

[juanito115]

Hi everyone! My name is Juan. I'm new to this forum. I have a friend who has a 99 trailblazer. It was making a horrible noise at start up. I knew it was probably the lifters. we changed the oil it kind of went away but came back! so I started reading this forum and find out that the lower manifold gasket could b at risk so, we decided to tackle it after reading lots of threads! I was hoping that it would be the lower gasket and not the head gasket, but in fact it was the lower intake gasket. It was all broken and made crap around the coolant ports. We're half way there!!! next thing today is to clean the gasket surface and both the lower and upper manifold. what's a good cleaner for this task? I'm going with carb cleaner. Sorry, no pics! (damn, I gotta buy a camera) I'll keep you guys updated!

[JoshBarber]

Originally Posted by juanito115

Hi everyone! My name is Juan. I'm new to this forum. I have a friend who has a 99 trailblazer. It was making a horrible noise at start up. I knew it was probably the lifters. we changed the oil it kind of went away but came back! so I started reading this forum and find out that the lower manifold gasket could b at risk so, we decided to tackle it after reading lots of threads! I was hoping that it would be the lower gasket and not the head gasket, but in fact it was the lower intake gasket. It was all broken and made crap around the coolant ports. We're half way there!!! next thing today is to clean the gasket surface and both the lower and upper manifold. what's a good cleaner for this task? I'm going with carb cleaner. Sorry, no pics! (damn, I gotta buy a camera) I'll keep you guys updated!

Check out this thread below, it states to use a razor blade and acetone:
http://www.automotiveforums.com/vbul...d.php?t=486234

[juanito115]

Well I got it as clean as possible with a scraper and a razor blade. I used brake cleaner too. seemed to get rid of all the carbon and oil pretty easy. we set the lower manifold and the upper manifold. I hope we don't get any leaks. I put enough rtv on the sides so it would seal nicely. also around the coolant ports. One of the fuel lines gave us some problem. It didn't wanna screw in as nicely as the other one, but we managed to get it going at the end. Today, we are going to put the dizzy back and tighten the upper manifold, hook up all the sensors, drain the coolant, drain the oil, flush the engine, and start it up!!!! wish me luck!

[doeyh]

Good Luck!
I will do the same job this weekend.
I should do as quickly as possible because NHL playoff will start.
If possible, give me some advices when it is needed.
I will post questions at "Coolant drips from edge of plastic intake manifold" thread.

Gooooooooood Luck!!!!!!!

How did you disconnect wiring from fuse box?
I pulled off fuse box, but, it is not connector. do I have to unscrew that?

[juanito115]

You know, I couldn't disconect it! I left it there. I managed to pull the upper and lower manifolds underneath the harness. I'm having a little problem! There are two ports in the back of the lower manifold and on the engine which are sealed or blocked. As I was cleaning around them I accidentally knocked off a little piece from one of the ports on the block. After me and my friend put everything back and filled the engine with antifreeze, we saw a huge leak under the car. coolant was dripping big time, so we had to take everything apart again. we were able to narrow that leak to the coolant port that I was talking about above. I think I didn't use enough rtv around it to seal it.

A couple of suggestions that worked for me (unfortunatelly I had to find out the hard way!!)

1. don't really need the ps puller. You can managed to get a 13mm open wrench behind the pulley to loosen the bolts and then just pull the bracket back to allow enough room for the wrench or socket to get to one of the lower manifold bolts.

2. Remove the distributor to allow more room to get the fuel lines disconnected. Do not remove the bolt holding the fuel lines bracket since it prevents the lines from moving around when loosening the lines.

3. Label all the sensors to make reconnections easier and faster.

4. When trying to get the upper manifold to seat against the lower manifold, you might encounter that it does not quite want to seat all the way. That's because there is a gasket that goes around where the injectors electrical connector goes and if it is dry it will not slide all the way down. Lube it up with engine oil also lube around the cpi opening and you'll see what a difference it makes.

Hope that this helps!! As I said, I'm stuck with the coolant leak around one of the blocked coolant passages. Hopefully that's the problem and hopefully it will get fixed tomorrow.

[muddog321]

Only thing to knock off is dex cool junk cause that passage gets capped by the lower intake on assembly. Did you run a good bead of RTV on the rear and front ends of the block and carefully lower the intake onto it. You may have pushed or made a bare spot when you reasembled it. Torque sequence is also critical on these and do it in 3 steps with the final at 132 in lbs or 11 ft lbs. (132 x .0833=11). I carefully pulled up and tied the main wire bundle out of the way and before I do the RTV and do a few trys on inserting and dropping into place the intake to ensure I have a clear path in avoiding the mess hanging around the compartment, especially the front PS bracket that can partial hinder the drivers side front corner of the intake and then the rear pass side the trans dip stick tube.

[doeyh]

According to other thread,
http://www.automotiveforums.com/vbul...d.php?t=486234
Torque is 35...
Who is right?

[herkyhawki]

get a manual and use the torque specs for 1999 year. If You overtorque these bolts, you will distort the block and cause main bearing failures!

[muddog321]

That post is the old CPI system used on pre-96 I believe models.
The 11 ft lbs is the correct torque for the 98 and later (anyone know on 96 and 97 - don't have the manual here) with the spider injection and yes it is very critical and even 11 ft lbs seemed like alot as the intake tightens down so you must use the correct sequence in 3 steps or it will leak!

[juanito115]

well, today I went back at it. We cleaned the old gasket material and ran a new bead of rtv. I hope we got that right this time. I did follow the torque sequence, hopefully I did not torque them too tight. I figurd it was like 10ft lbs. My torque wrench shows 20 only so I torqued them before 20 ft lbs. we are letting the gasket dry before we put everything the upper manifold and everything on. we want to add the coolant and see if there's any leaks. I'll check back onyou guys tomorrow!

[sebryce]

I just finished the same job on my 98 bravada 4.3 V6... I picked up a torque wrench from Harbor Freight tools (clicker type) and the Haynes manual called for 35 pounds. I torqued it in 3 steps; however, I could not torque higher than 30 lbs. and snapped two bolts. Had to remove and repeat (used a pencil eraser to remove one of the broken bolts, worked like a charm). A friend told me to just torque to 25 pounds and so far so good... Hope I did not over do it? Not sure if the $20 torque wrench was the problem... He also told me to return it and buy a Craftsman... While you have everything apart it is a great time to change the plugs, wires and oil cooler lines if they are leaking. Hope your manifold does not leak again, did you say you torqued to 20 lbs.? Have you had to change your heater core? On my vehicle day 2 and so far so good and no more oil leaks as well after changing the cooler lines.

[muddog321]

Don't want to sound like a broken record here but the correct torque is 11 ft lbs for 96 up (per Haynes - I looked it up) and NO GUESSING will get you thru this guys. It will leak or as stated above will cause distortion and possible bearing failure - this is per GM. The older 95 earlier CPI Blazers were higher.

[Jeremy Fitch]

The Specs are:

1996 on, 3 steps:

Step 1 - 26 in lbs or 2.17 ft lbs
Step 2 - 106 in lbs or 8.84 ft lbs
Step 3 - 132 in lbs or 11 ft lbs

Bolt pattern from front left to right is 7,8,1,4,3,2,5,6

[juanito115]

Ok so, we finished putting everything back together. The problem is that it doesn't want to start! There's fuel pressure, there's spark. There was a posibility that we could have put the distributor in the wrong way, so we took it out and looked for the TDC cyl 1. after that we set the distributor in and nothing so I took the dizzy out and turned it 180 degrees and nothing. What could be the cause. It does crank and sometimes sounds like it is going to start but it doesn't. CAn the rotor go in any position? I mean, you know how theres two screws holding the rotor, can I switch the rotor 180 instead of taking the dizzy out and rotating it 180 degrees?

[doeyh]

It is scary.... I have to do the same work like you.
I wish every luck to you.
I will keep an eye on this thread not to make this thing happen.