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New to me 99 Suburban: 5.7 vortec repairs

unabashedpraise

Adventurer
That statement basically answers itself, if the only difference is a replaced gasket then that is almost guaranteed to be the problem, if the gasket slipped or was damaged on installation it can allow the coolant into a cylinder, Rayra has a good point about the compression test but I would bet it is the gasket!! it sucks but sometimes this **** happens, the good thing is it will be easier to do it the second time! And make sure to use the felpro gaskets I posted earlier, any other gasket is an exercise in futility and they don't slip like the other type do!!
I did use the FEL pro kit.

I checked for combustion gases in coolant before I started the repair. Twice. No gases found per Lisle kit instructions.



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unabashedpraise

Adventurer
Any idea where to get a compression test tool? Tool rental?

So, taking all this in...
I need to do a compression test first? Then if it's good, take the intake back off?


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NevadaLover

Forking Icehole
Any idea where to get a compression test tool? Tool rental?

So, taking all this in...
I need to do a compression test first? Then if it's good, take the intake back off?
Yes just about any parts house does tool loan/rental so that's where to start looking for that!
and as much as it sucks I think you're gonna have to take the intake back off and probably find a problem there, did you coat the gasket with a light coating of motor oil? that is much needed step so it doesn't grab the intake when you set it down and tighten everything down, and one more step I always do is to use red loktite on the bolts because they can loosen up after a while, it's something I started doing and it seems to help in the long run!
Sorry about the bad luck but it really isn't that bad of a job, it isn't easy but it could be worse, believe me!!
Good luck!
 

NevadaLover

Forking Icehole
Assuming it's the intake, should I ahead and pull the heads?
No way, if the problem is the gaskets, and I bet it is, then you are just going to do the same job you just did, I.E. take everything off of the intake manifold, remove the manifold, replace the gaskets again and reinstall everything! the first time I did vortec intake gaskets I put the intake back on and wasn't careful enough and it pinched the gasket and caused a major leak, talk about cussing!! I will bet that is what has happened here and you will see the damaged gasket and the leak spot as soon as you get the manifold off, so leave the heads alone because these 5.7 heads don't have the problems that some of the 5.3's did and usually never leak!
 

unabashedpraise

Adventurer
No way, if the problem is the gaskets, and I bet it is, then you are just going to do the same job you just did, I.E. take everything off of the intake manifold, remove the manifold, replace the gaskets again and reinstall everything! the first time I did vortec intake gaskets I put the intake back on and wasn't careful enough and it pinched the gasket and caused a major leak, talk about cussing!! I will bet that is what has happened here and you will see the damaged gasket and the leak spot as soon as you get the manifold off, so leave the heads alone because these 5.7 heads don't have the problems that some of the 5.3's did and usually never leak!
I take it I'll need a new gasket kit? Just the intake gaskets?

I changed out the spider injectors too. Do I have to take the upper intake off as well?

Can I reuse the valve cover gasket?

If I have to get new I will, just hate wasting a good gasket if it's still OK.


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unabashedpraise

Adventurer
Also, maybe Simone should walk new through the intake gasket installation. I did see a few different versions. Some used copper, black, or red rtv. Some put a bead around the coolant passages. Nevadalover mentioned oil on the gasket. Etc...


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NevadaLover

Forking Icehole
NOTICE: Applying excessive amounts of sealant may prohibit the intake gasket from sealing properly.

intake1.gif

1. Apply a 4.0 mm (0.157 inch) patch of adhesive GM P/N 12346141 or equivalent to the cylinder head side of the lower intake manifold gasket at each end.
2. Install the lower intake manifold gasket onto the cylinder head.
Use the gasket locator pins in order to properly seat the lower intake manifold gasket onto the cylinder head.

intake2.gif

NOTICE: Care must be used to apply the correct amount of sealant onto the gaskets. Applying excessive amounts of sealant may prohibit the intake gaskets from sealing properly.

IMPORTANT: All sealing surfaces must be clean, free of oil, dirt, or any other foreign material.

3. Apply a 5 mm (0.197 inch) bead of adhesive GM P/N 12346141 or equivalent to the front top of the engine block.
4. Extend the adhesive bead 13 mm (0.50 inch) onto the each lower intake manifold gasket.

intake3.gif

5. Apply a 5 mm (0.197 inch) bead of adhesive GM P/N 12346141 or equivalent to the rear top of the engine block.
6. Extend the adhesive bead 13 mm (0.50 inch) onto each lower intake manifold gasket.

intake 4.gif


7. Install the lower intake manifold onto the engine block and the cylinder heads.

NOTICE: Refer to Fastener Notice in Service Precautions.

8. Apply threadlock GM P/N 12345382 or equivalent to the threads of the lower intake manifold bolts.

intake5.gif

NOTICE: Proper lower intake manifold fastener tightening sequence and torque is critical. Always follow the tightening sequence, and torque the intake manifold bolts using the 3 step method. Failing to do so may distort the crankshaft bearing bore alignment and cause damage to the crankshaft bearings.

9. Install the lower intake manifold bolts.
9.1. Tighten the bolts on the first pass in sequence (1-8) to 3 Nm (27 lb in).
9.2. Tighten the bolts on the second pass in sequence (1-8) to 12 Nm (106 lb in).
9.3. Tighten the bolts on the final pass in sequence (1-8) to 15 Nm (11 lb ft).


When I said thin coating of oil I meant a THIN coating and only on the top of the gasket on the rubber where the intake sits, and always use permatex ultra grey RTV where the instructions call for GM adhesive, and where the instructions call for a 4mm patch you just use a tiny amount of RTV not a thick strip, it is only there to help keep the gaskets in place not to seal a leak!
You will not have to remove the upper intake either, just the lower, and buy a new set but check out the old gasket and if it is not damaged you can reuse it and return the new set but chances are the gasket is going to be ruined, as for the other gaskets they should be fine to reuse!!
And NEVER put a bead around the coolant passages!! that is a sure way to get to do this job again, just follow these directions and you should be good to go for a LONG time, this is how I have done around 20 of these jobs and after the first failure I have never had to redo one!! Good luck and remember that this is just a test of your patience and you should pass this test easily!
 

unabashedpraise

Adventurer
NOTICE: Applying excessive amounts of sealant may prohibit the intake gasket from sealing properly.

View attachment 407624

1. Apply a 4.0 mm (0.157 inch) patch of adhesive GM P/N 12346141 or equivalent to the cylinder head side of the lower intake manifold gasket at each end.
2. Install the lower intake manifold gasket onto the cylinder head.
Use the gasket locator pins in order to properly seat the lower intake manifold gasket onto the cylinder head.

View attachment 407626

NOTICE: Care must be used to apply the correct amount of sealant onto the gaskets. Applying excessive amounts of sealant may prohibit the intake gaskets from sealing properly.

IMPORTANT: All sealing surfaces must be clean, free of oil, dirt, or any other foreign material.

3. Apply a 5 mm (0.197 inch) bead of adhesive GM P/N 12346141 or equivalent to the front top of the engine block.
4. Extend the adhesive bead 13 mm (0.50 inch) onto the each lower intake manifold gasket.

View attachment 407627

5. Apply a 5 mm (0.197 inch) bead of adhesive GM P/N 12346141 or equivalent to the rear top of the engine block.
6. Extend the adhesive bead 13 mm (0.50 inch) onto each lower intake manifold gasket.

View attachment 407628


7. Install the lower intake manifold onto the engine block and the cylinder heads.

NOTICE: Refer to Fastener Notice in Service Precautions.

8. Apply threadlock GM P/N 12345382 or equivalent to the threads of the lower intake manifold bolts.

View attachment 407629

NOTICE: Proper lower intake manifold fastener tightening sequence and torque is critical. Always follow the tightening sequence, and torque the intake manifold bolts using the 3 step method. Failing to do so may distort the crankshaft bearing bore alignment and cause damage to the crankshaft bearings.

9. Install the lower intake manifold bolts.
9.1. Tighten the bolts on the first pass in sequence (1-8) to 3 Nm (27 lb in).
9.2. Tighten the bolts on the second pass in sequence (1-8) to 12 Nm (106 lb in).
9.3. Tighten the bolts on the final pass in sequence (1-8) to 15 Nm (11 lb ft).


When I said thin coating of oil I meant a THIN coating and only on the top of the gasket on the rubber where the intake sits, and always use permatex ultra grey RTV where the instructions call for GM adhesive, and where the instructions call for a 4mm patch you just use a tiny amount of RTV not a thick strip, it is only there to help keep the gaskets in place not to seal a leak!
You will not have to remove the upper intake either, just the lower, and buy a new set but check out the old gasket and if it is not damaged you can reuse it and return the new set but chances are the gasket is going to be ruined, as for the other gaskets they should be fine to reuse!!
And NEVER put a bead around the coolant passages!! that is a sure way to get to do this job again, just follow these directions and you should be good to go for a LONG time, this is how I have done around 20 of these jobs and after the first failure I have never had to redo one!! Good luck and remember that this is just a test of your patience and you should pass this test easily!
I used the black rtv that came with the kit. How far up the head do you put the rtv? I did put a little on the gasket tabs that stick down towards the flat portion.

I also tightened three bolts in pairs as per FEL pro instructions.


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NevadaLover

Forking Icehole
The black RTV should probably be fine, and like the directions say go about a half inch up the heads to seal the valleys, follow the bolt patterns as they say in three steps and it should be good to go!
 

rayra

Expedition Leader
My comments about compression test before pulling the intake were meant just to narrow down where the fault might before dismantling things. And presuming you'd run it more to burn out any coolant that made it into the exhaust system after the initial teardown. If the smoke doesn't stop, if your coolant level goes down, if you get coolant out the spark plug holes during the compression testing, all of it means you have an fresh active leak somewhere.

In the past on SBC motors - which are very similar to the 1st gen vortec design, i'd use a light application of hi-temp rtv on the head side of the intake gaskets just to keep them stuck in place while I set the intake. The black RTV is good for the front and rear block walls of the galley space and the bead should be laid up onto the tabs of the intake gaskets. Or use light beads to stick the rubber front and rear gaskets / seals. You have to lower the intake carefully and don't ride anything. And follow the proper tightening sequence.

And with the two-part manifold(?) design in use here, it would be best to do it separately from teh rest of the mounted equipment. But it can be done leaving everything together. Just take care not to disturb the gaskets as you set the intake down on them.

I'm just not intimately familiar with these 1st gen vortec motors, just older SBCs and my newer Vortecs. The later models the intake manifold is completely 'dry', this becomes a total non-issue.

Been about a dozen years since I last did similar work on an SBC, after some pressed-in rocker studs failed on a remanf head

 

unabashedpraise

Adventurer
This time I was thinking about pulling the steering pulley off to be able to get to the bolts easier. Any of you know if it's have to pull the radiator to get to it? I'm at work and don't have the puller in front of me.


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rayra

Expedition Leader
power steering pump pulley? There's not really much room for a gear puller with the radiator shroud in place and a good chance of puncturing the radiator while doing it. You might be able to unbolt the fan shroud and shift it over enough to make room to operate a puller. But I suggest putting something flat / rigid in front of the radiator fins to protect them. even a section of cardboard will help.
 

NevadaLover

Forking Icehole
Power steering pulley? I've never had trouble getting the bolts off without taking the pulley off, that is a huge P.I.T.A. if you take the fan off you will have alot more room to work with and that's alot easier! Oh, and take the fan shroud off too, more room!
 

unabashedpraise

Adventurer
Yeah, I was having trouble getting the AC bracket out far enough the way last time. There were some bolts behind the pulley itself that were a giant pia to get to. I had to use a hacksaw blade and screwdriver to get one of them started back in!


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