Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter engine

Big Bubba

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Hello fellow Iboaters,
Well after I have owned my 2000 Chevrolet C3500, LS, Dually Pickup truck with 7.4 liter engine for a couple of months now I am having to replace the Lower Intake Manifold Gaskets on it since there pretty wet looking at the front side at the corners of the Intake Manifold and the biggest issue is water/coolant inside my oil when I check the oil dipstick that I discovered this past weekend. Anyway, I just picked up the intake manifold gasket Fel Pro Part No. MS 95826 and other stuff like the 6 quarts of Advance Auto parts 5W-30 oil and AC Delco oil filter and the 4 gallons of Peak full Strength antifreeze the 5 year stuff. Anyway, I tried to find the upgraded, metal, intake manifold gasket for my truck but cannot find it, is it available? My next question is what should I use to seal the four corners that the block and heads intersect when installing the intake manifold gaskets and should I place a bead of gasket sealant at the corners before I place the gaskets onto the surface of the heads and the two rubber pieces at the ends? I want to do a good job but the finer details are throwing me off somewhat. I also have did some on-line research and some people are putting the gasket maker stuff on around the water ports on a thin coat on both sides of the intake manifold gasket for added sealing protection against water/coolant leaks. Is that necessary? Another question, is there any particular order that the intake manifold gaskets go on, like, does the rubber end pieces go on first or does the plastic intake manifold gasket go on first? So to recap I guess my biggest question is, how to seal the four corners of the intake manifold gasket to the rubber end pieces? My next question is I guess the final torque, which I know is very critical to this job is a final torque of 30 foot/pounds. Is that correct? And the last question, marking the distributor before removal which is a big part of the job if you want the truck to crank up after the new gasket install. What is the best way or easiest way to mark the distributor so it is guaranteed to go in correctly once I start to put everything back together again after Intake manifold gasket install? Sorry for all the questions, I know I can do the job but some of the finer details and maybe some suggestions from the pro's on here will give me some pointers before I start this job this Friday after work. I will be working on this and getting this truck back together before Monday, 19 November 2012. So I have a date the whole weekend with my truck, LOL. Thank you for your help and suggestions any help sent my way will make my life better and hopefully the job will turn out perfect and correct. :confused:
 

rockyrude

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

What I do before the distibutor pull on my 350, I clean the base area at the distibutor well and spritz some light colored spray paint on the base of the distibutor and top of the intake. Then a sharpie makes a nice alignment mark. Then pull the cap and again with the sharpie mark on the housing where the rotor is pointing. Haven't had a no start in the six years I've had it. The Chiltons/Haynes will show a torque sequence for the manifold bolts which is critical to keeping the intake flat.
 

ajgraz

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

I have done aluminum LIM gaskets on at least 7 different 3800's, I know what you're going through.

It is my understanding that no one ever got around to doing an all-aluminum upgrade for the 7.4L. At least the FELPRO set does have metal torque rings around the bolt holes, which the OEM's did not have.

Black or orange RTV for sealing; a lima-bean-sized blob at each of the four corners before laying down the gaskets and end seals, then another similar-sized blob at each corner on top of the gaskets and endseals.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

RockyRude,
Awesome advice!!! That is what I am looking for, You Guys and this forum is the BEST!!! on the internet. Anyway, to recap what you just said is before removing the distributor clean the area at the base of the distributor and were it sits on the lower intake manifold with, say white spray paint and just a little bit of the white paint and then after that white paint dries then take a Sharpie, say red in color, and make a straight line from the lower intake manifold where the distributor sits on to the base of the distributor itself then once that is done you make one more mark by removing the distributor cap and making a mark from the rotor to the distributor housing. Then once thos two marks are made then you go ahead and remove the distributor. Is that correct? If so, that sounds easy enough. What about the sealing at the four corners of the intake manifold gaskets to the small rubber pieces that they intersect? I am not too clear on how to run the bead of sealant at or on? Thank you and keep the suggestions comming and I will be purchasing a Haynes manual before I start this also for this job.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

AJGraz,
Thank you Now I know exactly what to do concerning sealing up the four corners. recap, Before installing both the intake manifold gaskets and the rubber end pieces put a lima bean size bead in the four corners then install the two sets of gaskets and rubber end pieces then add another lima bean bead on top of them before installing the manifold down.

One more question, when installing the intake manifold is there any kind of guide pins/wooden dowels I could use to keep the gaskets from slipping out of place while carefully placing the intake manifold straight down on the gaskets?
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

One more question. I was wondering if I could get a copy of the lower intake manifold installation procedure for my 2000 Chevrolet Dually, 2WD, C3500, with 7.4 liter engine, sent to my inbox so I can download it and use it for the job?
 

ajgraz

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

AJGraz,
One more question, when installing the intake manifold is there any kind of guide pins/wooden dowels I could use to keep the gaskets from slipping out of place while carefully placing the intake manifold straight down on the gaskets?

Hmm, after 1995 the 3800 block had guide holes cast into it for that very purpose (the end seals have pins in the middle). Dunno whether the 7.4L will have anything like that. I guess if you let the RTV tack up 10 or 15 min before you place the gaskets and seals, it'll hold 'em in place.
 

rockyrude

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

I meant clean the area of the intake/distributor with your favorite degreaser so the paint will stay long enough for the job at least. Yes as to how/where to make the marks. The marks take all of the guess work out of reinstalling the distributor. Just remember, as the distributor comes out/goes in the rotor turns a few degrees because of the cam gear. You might want to put a second mark for the rotor/housing position just as the distributor comes out as a preset for reassembly. I doubt the 7.4 has changed much since it was introduced, like the 5.7 there aren't any pins for the gasket, so I use a couple of dabs of permatex #2 to hold the gasket in place while setting the intake.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Hello.
I have another question for you concerning the InTake manifold gasket repair job. Anyway, I noticed on the new Intake Manifold Gasket set that there is two large squares on the opposite ends and the rest are four round holes. Anyway, is the large squares on the ends where the coolant/water flows through and the four large round holes in the gasket the intake and exhaust holes? I was curious and wondering that is all.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

One more question,
Before I start this job, do I need to spray any sealant on the new intake manifold gaskets before installation. I have did research and some folks do tha but wondering if that is necessary?
 

rockyrude

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

I believe the 7.4 is similar to my 5.7 in that one intake passage on each side is actually blocked off with the gasket. On the 5.7 they use a steel insert in the gasket. Just look at the old gasket as things come apart to tell where insert goes. Also remember to pay attention to the "UP" stamped in the gasket.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

RockyRude,
Yeap, I looked at my new Intake manifold gasket and the words say this, "This Side Down" meaning, I guess, that the side that says this side down is sitting on the heads and you will not be able to see the words, "This side Down" once the gaskets are in place because you would have to flip the gaskets back over to read the words, "This Side Down". Thank you and I did find on-line the 7.4 liter upper and lower manifold tightening sequence which shows a picture and starting at the center of the intakes and working out in a circle with the upper intake, plenum chamber, being torqued in two sequences of 6 ft pound and 13 foot pound and the lower intake manifold torqued in two stages, first being 22 ft pounds then final torque of 30 foot pounds. Is that correct?
 

rockyrude

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Sounds correct to me.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Cool, I am ready to dive into this job and after reading your responses have made me feel alot confident in doing this job myself. I might get some half inch diameter threaded rods to use in the bolt hole corners as a guide so I don't move the gaskets around sitting the lower intake manifold onto the heads.
 

rockyrude

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Good luck with the rods, I've found on the 5.7 the angle of the heads puts the ends of the rods too close together to get the intake on.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

RockyRude,
I will probably just lower the lower intake manifold straight down onto the heads/block without the guide rods. Before I do though, I will practice a few times installing removing the intake on dry runs, without the new gasket being installed yet, until I fill confident that I can lower the intake down effectively without moving/disturbing the gaskets. I will also practice removing/installing the distributor a few times fter I have effectively marked the distributor at the base of the housing and where it intersects the top of the lower intake manifold and the rotor. Besides that I should be good to go.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Rockyrude/fellow Iboaters,
I was looking at different gasket sealants and they have a spray gasket at Autozone that you can spray on the intake manifold before installing the intake manifold gasket to the heads to keep the gaskets from moving when installing the manifold gaskets and to ensure added sealing. Here is the product at Autozone I am talking about. Would it hurt the gasket to use this gasket sealer in a spray can? Please click the link to view, Permatex/9 oz. aerosol can Copper Spray-A-Gasket hi-temp adhesive sealant (80697) | Gasket Sealant | AutoZone.com or what about this stuff, http://www.autozone.com/autozone/ac...-25c6?itemIdentifier=214303&_requestid=777327 or what about this stuff, http://www.autozone.com/autozone/ac...-25c6?itemIdentifier=554063&_requestid=778643 I seen the stuff in the can with the cue tip looking applicator that the guy used in a video to add to the water jackets of the heads and the water jackets of the manifold before sitting the manifold down and installing the lower intake manifold bolts. The guy said that the stuff in the metal can with the cue tip applicator was an added sealant to prevent leaks when installing the new lower intake manifold gaskets. What is your honest opinions out there am I going over board or is this a good ideal to add to ensure a 100% seal.
 

Big Bubba

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Hello Fellow Iboaters,
I am knee deep in changing out the lower intake manifold gaskets. Yeap, as you know, these gaskets are bad. One of the right rear water jackets is completely separated and broken in the plastic gasket. The other two are cracked but not as bad and the last one is in sad shape as well. I got alot accomplished today and have the new gaskets installed and the lower intake manifold torqued down to a final torque of 30 foot pounds. I will recheck the torque in the morning before proceeding on to installing the rest of the taken off. So tomorrow I plan on finishing this job and crank up the truck to make sure she is running good for me. Wish me luck
 

rockyrude

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Congratulations, sounds like you got the hard part done.
 

BlkY2k

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Re: Question about changing Lower Intake man Gasket on 2000 Chevy C3500, 7.4 liter en

Sounds great Bubba, you got alot done. Just remember the lower was in ft/lbs and the upper is in/lbs. Big difference
 
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