GM 3.4 V6 lower intake gasket...

[TilliamWe]

Yep, the one in 99 Montana van is leaking. One local shop quoted me over $1000 to replace it, flush the coolant, replace the thermostat, spark plugs, and spark plug wires. I am going to take it to another shop, but I am almost certain they are going to come up with nearly the same. (I paid over $700 for this repair on my 2003 Impala just two years ago. And in that case, it was the parts prices that were the killer.)
Since I want to use the $95 gasket kit, the $7 thermostat, the $30 wires, and the $4 ea plugs, as opposed to the $130 gasket, $16 thermo, $65 wires, and $7ea plugs, I can save over $100 in parts doing it myself.

But, my issue is time, and work area. I don't have very much free time, and no garage to do the work in. So I started reading the Haynes manual a little, and it describes having to remove the upper intake plenum and the individual injectors. If I didn't have to do this, and the whole manifold came off as an assembled unit, that would save TONS o'time.

So my question is for all the wrenchers, have you ever done this repair, and did you have to disassemble the entire intake manifold?

Thanks in advance.

 

[xtraham]

Re: GM 3.4 V6 lower intake gasket...

I've done many, and your answer is no.. you do have to remove the plenum but you can leave the injectors and fuel rail in the intake and remove it as a unit, it's a pain to remove the fuel lines from the rail (you have to get mad at them) and you'll need new O rings that will probably need to be ordered. Average book time on that job is around 6 hours, you can do it in 3 hours if you hump.

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

Thanks a ton for the info!

 

[Gary H NC]

Re: GM 3.4 V6 lower intake gasket...

Buy the Felpro Perma seal gasket set...

I did the job on my 350 myself in one day. I spent about 150 in parts.
The local shops all quoted around 8 to 9 hundred..

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

You are now the second person who says Felpro is the way to go. I think I believe it!

 

[dolluper]

Re: GM 3.4 V6 lower intake gasket...

You mighten want to replace your injector gaskets{o-rings} since you have the intake off ...just pay intention to the colours of the rings don't mix them up....my 2 cents

 

[v1_0]

Re: GM 3.4 V6 lower intake gasket...

Yep, the one in 99 Montana van is leaking. One local shop quoted me over $1000 to replace it, flush the coolant, replace the thermostat, spark plugs, and spark plug wires. I am going to take it to another shop, but I am almost certain they are going to come up with nearly the same. (I paid over $700 for this repair on my 2003 Impala just two years ago. And in that case, it was the parts prices that were the killer.)
Since I want to use the $95 gasket kit, the $7 thermostat, the $30 wires, and the $4 ea plugs, as opposed to the $130 gasket, $16 thermo, $65 wires, and $7ea plugs, I can save over $100 in parts doing it myself.
.

There's a couple of places local here that will let you bring whatever parts you want and the'll do the labor. You do have to sign a waver ("we are not liable for crappy parts, etc..."). I tend to do this when I get my F350 worked on, as the mark up on oils, etc. is killer.

-V

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

v1 0 I sure wish there was someone around here that would let me do that, but alas, there is not.

Thanks dolluper. But if I don't take the injectors out, why would I want to replace the o-rings? Do they start to crack after 10 years?

 

[xtraham]

Re: GM 3.4 V6 lower intake gasket...

v1 0 I sure wish there was someone around here that would let me do that, but alas, there is not.

Thanks dolluper. But if I don't take the injectors out, why would I want to replace the o-rings? Do they start to crack after 10 years?

no they don't, if you pull the injectors per the book they will leak with the old O rings, like earlier... I pull the intake as a unit it saves a bunch of time and hassle

 

[dolluper]

Re: GM 3.4 V6 lower intake gasket...

I just hate call backs....with the heat over time well you know and I call it preventative maintenence......it's your choice

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

I understand what you are saying, both of you. In this case, the call back will be mine to deal with, not to pay someone else.
It's the initial time needed to do the repair that had me looking for the least disassembly time as possible.

 

[Xcusme]

Re: GM 3.4 V6 lower intake gasket...

A couple of tips.... Do not mix up the push rods...trust me...poke them through a piece of card board in the order and placement that you remove them. Clean the gasket surfaces spotless, no oil, no nothing before you mount the gasket. Don't over tighten the intake bolts, I know the newer gaskets have stop blocks to prevent crushing, but follow the destructions on assembly.. Your motor is a PITA to do the repair on, little room to work. Plan on removing the front Dog Bone to tilt the motor etc.

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

Yeah, tilting the motor is one of the first things it describes. That is also the reason why my engine only has three new spark plugs! he he ( I was too lazy that day!)

Somewhere in the Haynes manual (and from a small town mechanic a few years ago) I saw that the torque values for some of the intake bolts are greater than the rest. Will the FelPro gasket set come with instructions of their own? And if they do, I'll definately follow theirs, cause my faith in GM (or Haynes to interpret GM) in this matter is not high. I mean they made these junk gaskets for how many years, before they admitted the problem???

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

I bought all the parts yesterday, with the intention of using a three day weekend to work on it. Of course, the weather forcast changed yesterday evening, and now it's gonna rain all weekend, into Tuesday! I love Central Illinois! And I really love not having a garage!
BTW, the parts were $135 total, including an unrelated $15 cabin air filter! So I can't justify having anyone else do the work, I just have to do it myself.

 

[dolluper]

Re: GM 3.4 V6 lower intake gasket...

Here's a link that might help you or others.....go to MY ZONE on left side of page register. put in your vehicle info then use the repair guides I took a fast peak they have info on doing your intake with Pics.....you might find it usefull as others might link below LOOK UNDER ENGINE
http://www.autozone.com/autozone/ho...4F91DCAFB4E447DB4A3B4D32B4E3C0.diyprod5-b2c15

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

Thanks dolluper. I didn't register, but are the repair guide and pictures from the Haynes manuals they sell at the store? if so, I already own the one for my van. But for those that don't want to buy the $15 book, online for free is a good thing.
Thanks again.

 

[sportsmanphil]

Re: GM 3.4 V6 lower intake gasket...

Ive replaced a few hundred over the years.

IMO, buy the factory gaskets, depending on the year of your van, you might have the old gaskets and will get the revised sets from GM.

DO NOT, DO NOT, DO NOT over torque the lower intake bolts! 90% of the replacement gaskets leaking are due to too high a torque on the bolts.

Remove the torque strut mount (AKA dog bone). Put the trans in park with the E-brake off. Standing out the drivers door, push and pull the van back and forth. This will cause the engine to rock back and forth, when the engine rocks forward, hit the E-brake. It will hold the engine for ya

One problem area is the water outlet fitting. It has a "quick disconnect" but it sucks. Usually when you take it apart, it never seals going back together. Some techs just used a large wrench and backed the quck connect fittiing otu of the intake. Just remember you will need some pipe fitting compound when putting it back together.

While you have the upper and lower intake out, might want to consider valve cover gaskets and replacing the plugs, its real easy with all that crap out of the way and the engine rocked forward.

*******

Someone recently posted a link for a class action lawsuit for the intake gasket replacement on 3.1 and 3.4 engines. People have been getting their money back for clogged cooling systems too because of the Dexacool. Might want to do a google search on "class action, GM, dexacool". Might get it done for free.

 

[dolluper]

Re: GM 3.4 V6 lower intake gasket...

Don't know if it's the same as Haynes but it's not bad for a reference before you dive into the fix .....the beauty is it's free and you can do maintance schedules and look at mutiple vehicles repair guides.....methinks they have a contract with alldata but not a complete one to bad.....but hey foe free not to bad and you don't get any spam from it ....of corase unless you want it

 

[TilliamWe]

Re: GM 3.4 V6 lower intake gasket...

Remove the torque strut mount (AKA dog bone). Put the trans in park with the E-brake off. Standing out the drivers door, push and pull the van back and forth. This will cause the engine to rock back and forth, when the engine rocks forward, hit the E-brake. It will hold the engine for ya

One problem area is the water outlet fitting. It has a "quick disconnect" but it sucks. Usually when you take it apart, it never seals going back together. Some techs just used a large wrench and backed the quck connect fittiing otu of the intake. Just remember you will need some pipe fitting compound when putting it back together.

While you have the upper and lower intake out, might want to consider valve cover gaskets and replacing the plugs, its real easy with all that crap out of the way and the engine rocked forward.

*******

Someone recently posted a link for a class action lawsuit for the intake gasket replacement on 3.1 and 3.4 engines. People have been getting their money back for clogged cooling systems too because of the Dexacool. Might want to do a google search on "class action, GM, dexacool". Might get it done for free.

Thanks for the trick on the engine rocking. I don't have a good ratchet strap to hold it, so I will try your tip.
I have heard of the cooling outlet issue. I *think* I had that exact same issue with my 1990 Cavalier. The plastic retainer broke. The mechanic removed the hole fitting and replaced it with a brass one, hose, and hose clamps. Worked perfectly for 5 years, and beyond when I sold the car. Thanks.
Spark plugs and wires are purchased and will be changed. I'll leave the valve cover gaskets alone, if I can. I *think* the gasket set i bought might contain them, though. maybe not.
The time window on the class action lawsuit has closed. Basically this would have to have happened before last September. I'm out the money.

dolluper, I'll probably go ahead and sign up, just to take a look, then. Thanks again.

 

[sportsmanphil]

Re: GM 3.4 V6 lower intake gasket...

Let me correct my last post. You will have to pull the valve cover gaskets anyway. The way the intake and valve cover's overlap require the removal of the v-covers.