New to me 99 Suburban: 5.7 vortec repairs

rayra

Expedition Leader
If it's like my pickup, it's a lot easier to leave the PS pump on that inner bracket and remove the hardware trapping the bracket. Especially with that bolt on the back of the pump inboard of the hydraulic piping. Take out the outboard bolt that locks the belt tension down, leave the back one in place. Take out the AC mount bracket that's bolted onto the exhaust manifold stud and front of the head / intake (which I think traps the upper attachment of the PS pump bracket, and the PS bracket nut between the PS and water pumps. Just leave the whole bracket attached to the pump and flex the whole mess over into the front right corner of the engine bay. Put some coathanger wire on it to hold it out of the way.
 

rayra

Expedition Leader
what is this wetness along the manifold mating surface, lower right of center? Looks like coolant?




The intake manifold gaskets look like they were mounted ok, but they don't seem to fit / align very well. Don't like the look of the dogleg design and its fitment, in the lower inboard corners of the crossover passages, although your galley area doesn't look like there was coolant mixing in it. I'm not familiar with that two-part intake design, don't know how the wet and dry passages are separated or penetrated. But that would seem to be the place where coolant is getting where it shouldn't and is being ingested. How is coolant carried thru it and what does the surface on the upper half of the intake look like? Any signs of coolant around the fuel injector ports?

Also don't like the look of your mating surface cleanup in those head surfaces. That needs to be smooooth. Looks more like a quick pass with a scraper, with some gouges and some original gasket material left behind. I'd suggest another careful pass at that with a sharp scraper, and maybe even some careful block sanding with some high grit / wet/dry. Every rough area where that intake gasket crosses over is a chance for a leak.

I'll go study up on that intake manifold design and see if I can come up with any other bright ideas.
 

unabashedpraise

Adventurer
what is this wetness along the manifold mating surface, lower right of center? Looks like coolant?




The intake manifold gaskets look like they were mounted ok, but they don't seem to fit / align very well. Don't like the look of the dogleg design and its fitment, in the lower inboard corners of the crossover passages, although your galley area doesn't look like there was coolant mixing in it. I'm not familiar with that two-part intake design, don't know how the wet and dry passages are separated or penetrated. But that would seem to be the place where coolant is getting where it shouldn't and is being ingested. How is coolant carried thru it and what does the surface on the upper half of the intake look like? Any signs of coolant around the fuel injector ports?

Also don't like the look of your mating surface cleanup in those head surfaces. That needs to be smooooth. Looks more like a quick pass with a scraper, with some gouges and some original gasket material left behind. I'd suggest another careful pass at that with a sharp scraper, and maybe even some careful block sanding with some high grit / wet/dry. Every rough area where that intake gasket crosses over is a chance for a leak.

I'll go study up on that intake manifold design and see if I can come up with any other bright ideas.
The upper intake liquid is oil. No coolant.

Lower valley had coolant in it. Lots of coolant around front passages.


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rayra

Expedition Leader
so I see now that the upper is 'dry' and that there are no coolant passages between the lower intake and the upper. Is it possible that your lower intake manifold is cracked and passing coolant into the 'air' side of things?
If not, then it's got to either be the lower intake to heads gaskets not sealing properly or you do have a head gasket problem.

https://youtu.be/8RffhTSAZM4?t=1303
 

unabashedpraise

Adventurer
so I see now that the upper is 'dry' and that there are no coolant passages between the lower intake and the upper. Is it possible that your lower intake manifold is cracked and passing coolant into the 'air' side of things?
If not, then it's got to either be the lower intake to heads gaskets not sealing properly or you do have a head gasket problem.
I'm thinking it was my torque pattern. Fel pro said to do it in pairs. I didn't do it in individual crisscross pattern, but a pair crisscross pattern. Oh and the new gasket had this:



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rayra

Expedition Leader
geez, that's only the primary sealing ridge.
At this point I'd be tempted to put some ultrablue RTV on both sides of the crossover gasket surfaces, even with a new gasket and give it an overnight cure before I run it.

you changed the o-rings in the upper intake shell too?
 

unabashedpraise

Adventurer
geez, that's only the primary sealing ridge.
At this point I'd be tempted to put some ultrablue RTV on both sides of the crossover gasket surfaces, even with a new gasket and give it an overnight cure before I run it.

you changed the o-rings in the upper intake shell too?
Yes, new gasket. It will sit for a few days before I can start it.

Mistakes I know I made are: not using property torque sequence, no rtv up the gasket .5", buying a suburban I knew needed an intake repair


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NevadaLover

Forking Icehole
Definitely return that gasket for a new one and open/inspect the new set before you leave the parts house!

Now for the block and heads, your next job needs to be taking a scraper to every surface that the gaskets and intake sit on, they need to be clean and dry before you reapply the RTV and gaskets, take a pick and clean the bolt holes and scrape anything that you can feel with your finger, take a pick and clean the bolt holes, the surfaces need to be smooth! use a rag to stop the chunks from falling into the valley and wipe the scraper off continuously while you are working.

Also get 5 or 6 cans of carbkleen, not brakekleen, carbkleen! take out the oil drain plug and drain the crankcase, then just spray all the crap out of the valley into the engine, it will drain down and run out so don't worry! when you get everything clean pour a clean quart of oil all over the valley to help rinse all the residue out the drain, then reassemble the intake as per the instructions then put the drain plug back and refill the engine oil, be sure to service the engine, filter and oil in about 100 miles to make sure you get it clean and everything should be good!!

Oh and once you get everything back together don't start and run the engine til tomorrow, the RTV needs to set-up, and starting it too soon will cause problems so let it sit!
 

NevadaLover

Forking Icehole
geez, that's only the primary sealing ridge.
At this point I'd be tempted to put some ultrablue RTV on both sides of the crossover gasket surfaces, even with a new gasket and give it an overnight cure before I run it.

you changed the o-rings in the upper intake shell too?
NO, don't put any RTV ON the gaskets at the coolant passages, these gaskets will slip as soon as you get RTV on them, the only place to put RTV is where the directions say too, I know it sounds like a little extra insurance but these gaskets and RTV don't like each other and do not get along!
Don't ask me how I learned that!:mad:
 

NevadaLover

Forking Icehole
If you have a shop vac it will help immensely in the clean up, use it to suck up all the oil and coolant then use it to suck up any chunks of crap that you see while cleaning!
 

rayra

Expedition Leader
when I did the intake gasket adn knock sensor swap on my '02 Sub I stuffed paper towel in all the intake runners in the heads, before scraping. And I used some brakleen on a terry towel as a cleaning scrubber after the scraping. And after vacuuming the debris from the head ports I likewise used the brakleen towel to scrub the filth out of the ports.


The small bent pipe across the front of the motor is the crossover in the later-generation Vortecs








Had to do a lot of scrubbing and cleaning to get all the crust off the intake manifold and injectors, and put a couple bottles of injector cleaner additive thru the tank afterwards. This was on the Suburban, not the Tahoe.





Nevada, I'd like more details on why it's such a terrible thing? These later gaskets with their o-ring style design certainly seem better than the older flat designs, but I'd like some explanation of why a light application of RTV would be bad? With a proper torque down, I don't see how it could make things worse. And if the mating surfaces are gouged up, the o-ring isn't going to block it all. It would seem even more necessary to add some RTV to fill any gouges.
As a side note I have not done so on either of my GMT800 vortecs, frankly I was amazed at the mirror-like finish on the milled aluminum surfaces even at 12-15yrs and 100k+miles. I took careful pains to NOT mar them when cleaning them up. Even used some plastic scrapers as I worked off the crud, rather than my sharp bladed engine scraper.
But an older head or intake that's marred or gouged, I'd want to put a dab of RTV anywhere I could see such an issue. Especially if I couldn't scrape or sand it out.

eta I also really like how the later designs basically snap / lock in place. The old SBC problem of accidentally shoving a gasket out of place is nigh impossible with the newer designs.

and a pox on photobucket for destroying all my prior posting work and making it much more difficult to retrieve prior images.
 

NevadaLover

Forking Icehole
Nevada, I'd like more details on why it's such a terrible thing? These later gaskets with their o-ring style design certainly seem better than the older flat designs, but I'd like some explanation of why a light application of RTV would be bad? With a proper torque down, I don't see how it could make things worse. And if the mating surfaces are gouged up, the o-ring isn't going to block it all. It would seem even more necessary to add some RTV to fill any gouges.
As a side note I have not done so on either of my GMT800 vortecs, frankly I was amazed at the mirror-like finish on the milled aluminum surfaces even at 12-15yrs and 100k+miles. I took careful pains to NOT mar them when cleaning them up. Even used some plastic scrapers as I worked off the crud, rather than my sharp bladed engine scraper.
But an older head or intake that's marred or gouged, I'd want to put a dab of RTV anywhere I could see such an issue. Especially if I couldn't scrape or sand it out.

eta I also really like how the later designs basically snap / lock in place. The old SBC problem of accidentally shoving a gasket out of place is nigh impossible with the newer designs.
First, the new gaskets are designed to be put on dry, I use a light coating of oil on the intake side to keep it from grabbing when the intake goes on and is tightened down, these gaskets and RTV create some kind of chemical reaction and will not bond to each other and will squeeze away from each other with the slightest pressure creating a HUGE leak that will make you consider burning the truck to the ground, a feeling I believe unabashed knows very well right now!! using RTV on a captured gasket like the LS intakes is okay because the gasket has nowhere to go, but on a sandwiched gasket like the 5.7 vortec it will come out like nacho cheese through a pitbull!

Second, when GM designed the LS series engines they did make some changes that were seriously needed, and some that are completely assinine!! But one of the important changes was to go to a dry intake and got away from the HORRIBLE 96-99 vortec small block intake that was a stupid design on a great long block, the simple intake makes coolant leaks into the engine a thing of the past!

Third, Brakleen if not used carefully will do horrible things to any plastic it hits, melting insulation, making electrical plugs brittle as hell, so I always use carbkleen instead!
 

rayra

Expedition Leader
wasn't aware of that interaction, having skipped those model years. interesting info and I'll keep in mind

non-chlorinated brakleen works well. I also typically use it as a firearms cleaner, lot cheaper than purpose-brnaded sprays. Works fine on many firearms plastics. But always, the caution is 'test on a small area'. But the only place I reall flood it on is where it's meant to be used, cleaning brakes.
 
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