Chevrolet 5.7 intake manifold removal/replace.

[Rumble]

I'm removing the intake manifold (replacing gaskets) on my '92 Chevy pickup (C1500 w/5.7). I may be asking a few questions to get me through this ordeal. :eek

First up, how do I remove this heater hose connected at the manifold? Second, what is that round doo-dad that looks like some sort of vacuum device (it doesn't need removing, just wanted to know what it is)? Thanks.

 

[daman]

pinch the two tabs on the heater hose and pull out,it may be a struggle,the other is your EGR valve

 

[Rumble]

Thanks daman!

 

[daman]

No problem good luck..

 

[abycat]

Yeah +1 Make sure you can get a replacement or have one of the plastic piece. Some parts get a little hard to find and the heating and cooling will weaken the plastic over time. I like going to the local pull your part and grabbing a few pieces that look like they could be trouble when im doing something more major like that.

You can also get some experiance on the junk yard motor before trial and error with your engine.

Also if the egr valve has no hose for it the port on the tb needs to be at least capped off for the a/f ratio to be closer to correct.

 

[bullwinkle]

Careful with that heater hose fitting-you'll never get that plastic [CENSORED} out in one piece!

 

[cchase]

This would be a great time to check the operation of the EGR valve and replace the distributor cap and rotor.

 

[FL_Rob]

replace it with a compression fitting.
as far as you get into the motor ..replace whatever you touch..Not always needed but recommended.

 

[Rumble]

Thanks for all the tips/advice everyone. The manifold is off. Biggest headache was the distributor hold-down bolt! I've got to get everything cleaned up, and see what other odds and ends I need to replace while I have the unit off.

My next question is regarding the 12 bolts that hold the manifold down. Do I need to put any kind of sealant on the "bolts" when I re-assemble? And, what about the gaskets (they're GM ACDELCO), put them on dry, or use sealant?

 

[Chris142]

I use Teflon tape on those intake manifold bolts. If you don't seal them oil somehow travels up them and leaves oil on the top.

 

[Rumble]

Originally Posted By: Chris142
I use Teflon tape on those intake manifold bolts. If you don't seal them oil somehow travels up them and leaves oil on the top.


Thanks Chris, that sounds good.

 

[Merkava_4]

Originally Posted By: Chris142
I use Teflon tape on those intake manifold bolts. If you don't seal them oil somehow travels up them and leaves oil on the top.


I've been using Permatex 2B (dark brown sticky stuff) for that purpose.
I'm not saying it's better than Teflon tape; just saying it works for me.

 

[Ojustracing]

That coolant fitting looks likes its leaking or going to leak. They corrode, leak and then break off when trying to remove it. Its alot easier to remove the fitting when the manifold is on the bench.

 

[The_Eric]

Originally Posted By: Merkava_4
Originally Posted By: Chris142
I use Teflon tape on those intake manifold bolts. If you don't seal them oil somehow travels up them and leaves oil on the top.


I've been using Permatex 2B (dark brown sticky stuff) for that purpose.
I'm not saying it's better than Teflon tape; just saying it works for me.


Yep, #2B works really well for a variety of applications.

Also agree that the coolant fitting needs replaced. One of the few Dorman/HELP line parts worth using are those steel quick connects. They can be found at most auto parts stores.

 

[Rumble]

Originally Posted By: Ojustracing
That coolant fitting looks likes its leaking or going to leak. They corrode, leak and then break off when trying to remove it. Its alot easier to remove the fitting when the manifold is on the bench.


That fitting was replaced just a few years ago (corrosion as you mentioned). The picture shows some sort of reddish sealant/compound that I have now cleaned off.

 

[dakota99]

When you put the manifold back on be sure to use a good torque wrench and tighten the bolts in the proper sequence. Also if your gasket set didn't come with the front and back rubber gaskets, put a 3/16" bead of rtv on the front and back of the engine where the manifold meets the block. You should also extend this bead about a 1/2" inch upwards on each side to seal the corners.

Here's the torque sequence. Final torque is 35 ft lbs. If you want, you can follow this sequence or just do them in sequence to 35, i'm not sure it matters but these were the instructions for my dakota.

bolts 1-4 12 inch pounds
bolts 1-4 24 inch pounds
bolts 1-4 36 inch pounds
bolts 1-4 48 inch pounds
bolts 1-4 60 inch pounds
bolts 1-4 72 inch pounds
bolts 5-12 72 inch pounds
All bolts 12 foot pounds

My final torque was 12 foot pounds, but your chevy specs 35 foot pounds, so you could just go ahead and do 35 from 12 in sequence, whichever you like. I just figure the stepped sequence ensures even tightening.

 

[mechtech2]

Permatex #2 is great for those bolts.
T tape is a pain, and questionable.

Sealant is not normally recommended by good gasket mfrs.
But I really clean [Scothbrite the mating surfaces of the head and manifold.
And sometimes I DO use silicone RTV around the water holes.

The end gaskets/seals should use RTV at their ends. Sometimes, I use some on the whole thing, but watch out for squeeze out on assembly.
This is one item that really should be snuck up on, torque wise. You want that manifold to seat evenly.

For instance, doing one side then the other is way wrong!

 

[Rumble]

Thanks Dakota and mechtech, great info. I should have the mani ready for re-installation tomorrow afternoon. I've got to round up a 3/8" torque wrench, my 1/2" is too large for those center bolts.

 

[Rumble]

The manifold is on, I'm gonna start hooking things up tomorrow, and also take the throttle-body injection unit apart and clean it up while it's off. I should be ready to fire it up on Monday. I bought this truck new in 1992, been with me a while! Thanks for all the help and advice everyone.