intake manifold removal, fuel injectors and torque

[jbecker906]

I have a 3.4 liter 97 trans sport and I'm in the middle of this process, too. My Chilton's manual is not clear about the several things:

Can someone tell me why I should even have to remove the fuel injectors and rails from the lower manifold. Why not just pull the manifold with the injectors still attached? If I do have to remove the injectors, do I really just pry on the rails to pull the injectors out?

I did remove the back valve cover completely, but can not remove the front valve cover because of this metal coolant line....after removing the one screw on its flange, it still is pretty well stuck in place. Is brute force needed at the flange or am I missing something that is still holding this in place...... or is removal even nesessary since the back cover is off?

Finally, the manual does not show the pattern or torque spec for the 3.4 liter engine. Can someone help? To be clear, the eight bolts can be described as number 1 through 8, left to right, front to back.

thanks,

Jim

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['97ventureowner]

Try this link : http://www.automotiveforums.com/vbul...d.php?t=321467 In particular post #24 might answer part of your question. The Venture is similar in design to the Transport so these posts are also usuable to you. Some of the posts within that thread contain links to TSBs and other new info that can help you.

[eleveniron]

Hi Jim,

Once you remove the one bolt from the flange of the metal coolant line it should come out without too much force. It's just stuck on the o-ring a bit. Wiggle it around as you pull it straight up.

You could lift ot the lower manifold with the injector rail still in, however i would recommend you take it off first. The injectors are also stuck on the o-rings and it doesn't hurt to use some light oil like WD-40 or LPS. Spray each injector at the base wheer it is stuck into the manifold and the oil should free up the orings. Don't pry too hard or you could bend the rail. Just work on each injector a little at a time. The reason I say you will have to remove it anyway is because when it comes to handling and cleaning the manifold after removal, you don't want to risk damaging or contaminating the holes on the injectors.

Here are the instructions for installing the lower manifild bolts. Very important to tighten the 4 center bolts before the 4 diagonal bolts on the ends. It doesn't say so, but you should use a typical criss-cross pattern when torqing the bolts.

Also, in addition to the instructions below, pay attention to this note which is a revison to the original install procedure regarding application of the sealant...


1. Install the intake manifold gaskets.

2. Apply small drops (8-10 mm [0.31-0.39 in]) of RTV sealer, GM P/N 12346286 (in Canada, use GM P/N 10953476) or the equivalent to the four corners of the intake manifold to block joint (1).

3. Connect the small drops with a bead of RTV sealer that is between 8-10 mm (0.31-0.39 in) wide and 3.0-5.0 mm (0.12-0.20 in) thick (2).

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

Install the lower intake manifold.
Apply sealant GM P/N 12345739 at engine block to manifold mating surface. Bead should be 2.0-3.0 mm (0.08-0.12 inch) wide and 3.0-5.0 mm (0.12-0.20 in) thick.
CAUTION: Failure to tighten vertical bolts before the diagonal bolts may cause an oil leak.

Install the lower intake manifold retaining bolts.
Apply sealant GM P/N 12345382 to the threads of the bolts.
Tighten the vertical bolts to 13 Nm (115 inch lbs.) .
Tighten the diagonal bolts to 13 Nm (115 inch lbs.) .

Install the heater inlet pipe assembly.

NOTE: Do not press on the fuel pressure regulator assembly valve when installing fuel injector rail assembly.

Install the fuel injector rail assembly.
Lightly lubricate the fuel injector O-rings using GM P/N 1051885.
Install the injectors of the fuel rail assembly into the bores of the manifold.
Carefully press on the injector rail with the palms of both hands until the injectors are fully seated.
Install the fuel injector rail bolts.
Tighten the bolts to 10 Nm (89 inch lbs.) .

[jbecker906]

Thanks for the reassurance and the info! This really helps.

One follow-up to the torque spec - the diagonal bolts are hard to reach without a u-joint on my torque wrench. Should I do some math to account for the angle? Trust my sense of touch and use a small wrench..... or is there a small torque wrench at the auto shop that will fit in there?

By the way, I noticed that at least one bolt was quite easy to turn compared to the others..... the one that is near were I am loosing coolant, of course. Isn't thread lock suppose to prevent this? I haven't removed any bolts, yet. But, I'm interested in whether normal temp cycling can cause this problem.

thanks, again

Jim

[eleveniron]

Jim,

Yes, a couple of the diagonal bolts you won't be able to get straight on. I ballparked the torque on these by hand either witha wrench or socket and universal. If you haven't already done so, remove the power steering pump to get at the 2 diagonal bolts easilly on the RH side...remove 3 bolts for the pump (through the holes in the pulley) and disconnect the steel line. You can leave the rubber line connected and you'll have lots of room to move the pump out of the way.

All 8 of my bolts were hand tight or less when I removed them. This was one of thr reasons GM revised the torque procedure. They also tell you to use all new bolts becasue the new bolts come with a better thread lock than before. I cleaned my original bolts and used red loctite...they're not going anywhere now. Poor torqing procedure, poor thread lock and crappy gaskets all contributed to the loss of torque on these bolts which leads to the coolant leak past the gasket.

Also, don't be shy with the RTV in the 4 corners before you drop the manifold in.

Have fun!
Steve

[jbecker906]

Thanks Steve, This was very good and clear info. I bought blue thread lock only because I'm probably too trusting of the guys at the auto parts store, even when they use the word "should"...... I'll use the red.

Still a little confused about your reference to silicone on the "corners". I thought I was supposed to create a continuous bead around the whole thing?

Thanks for making the struggle easier.

Jim

[eleveniron]

Hi Jim,

Did you get the steel heater line out?

Yes you will need a bead of it where there are no gaskets, but use extra in the four lower corners where the heads, lower manifod and block all meet. The bulletin tells you to use a blob of about 1 cm in each corner. Just because you have multiple seams there. I put my manifold in place before I put on the RTV just to check the fit and there is definately potential for an oil leak in those corners if not enough sealant.

Same thing where the valve cover gaskets contact the lower manifold. You'll see a bit of a wedge section on the valve cover gasket. I put extra RTV around there too. You really have to get into all thsoe areas and clean VERY well with a good parts cleaner to make sure the RTV seals properly.

Are we having fun yet?

Cheers!

[jbecker906]

Thanks eleveniron,

I was traveling this weekend...... gave my back a chance to rest and my knuckles a chance to heal, so I haven't had a chance to do any more work since posting.... hoping for some time tonight.

I see you live across the pond from where I grew up (Grand Marais).... We live in the tropical part of Michigan now, but I'll wave to you from the shore next time we get up there.

[eleveniron]

OK Jim,

Let me know if you have any questions. If it makes you feel any better, I'd do the job again if I had to. A lot quicker the second time I'm sure.

Grand Marais...consumed a few pizzas and pitchers of beers at Sven & Olie's over the years.

Steve

[jbecker906]

Steve - I meant Grand Marais, Michigan - too far to drive for pizza and beer.

[eleveniron]

Ah...I thought you meant Wisconsin...1 hour from here.

[jbecker906]

Steve - Just wanted to thank you again for the help. Everything went pretty well..... no leaks, and runs better with new plugs and wires.

thanks again,

Jim