OT - '99 Tahoe Intake Gasket R&R????

This is off topic I know but I need help.

My '99 350 Tahoe is leaking coolant into the exhaust. I hate working on a late model but if it saves me $600-$800... I don't have much choice.

I hear this is a common problem. I also hear that this is a plastic intake & that the bolts are only torqued to a certain #. Also that the bolts may need some "glue".

Anyone ever done one of these? Anything in particular I need to watch out for? Any GM techs or mechanics who could offer advice..... or scans of service manuals?

TIA, JH

 

I would like a good answer on this one too. My 97 burns alotta coolant to.

 

Had it done on a '99 a few years ago, cost about $400 in labor. Distributor has to come out and be resynced too.

 

If its the older style plastic injectors,Be real careful with them.They are a spyder style that are inside of the intake.When you take it off,Try not to spray alot of brake cleaner on them when cleaning the gasket surface.They are pretty tempermental and fall apart.Just unbolt the intake like you would normally do on any sbc.Remove the fuel lines from the rear.Be careful of the heater hose ******.Check it real good.They normally break or leak from there.Pull the dizzy out and you should be good to go.Clean,lay out the gaskets and put a nice bead of your favorite sealer on the front and rear of the intake.If it has A/C you will need to remove some of the bolts that hold it to the block and also alt braket bolts too, if I remember correctly.I did one a few years back.They are not to bad to do.

I am sure that someone will chime in on the torque specs.

 

I did it a couple of years ago. A really big pain in the ***. You remove stuff for a day or so and finially get down to the manifold. The gasket is plastic with a O-ring built into it for sealing. Torque on the bolts is critical. Too much and it squeses out. Too little and no seal. I had hell just getting the manifold to actually lift off due to stuff on the engine. I made alignment pins from some all thread so the manifold would drop down and not move the gaskets. I wish I had painted everything for corrosion protection. My son sold the car last month. Held till then at least.

 

Dont use the plastic gasket!!!!!!!!!!!!!!!!!! Fel Pro makes a rubber and metal gasket that will fix the problem. The torque specs are inch lbs and yes you have to use blue lock***e on the bolts. The upper plenum does not need to come off you can pull the manifold without pulling the plenum.

 

Go to a good parts store and request the Fel/Pro gasket upgrade for this application. G-M stock gasket made of plastic,Fel/Pro upgrade has a steel core structure.

 

just did one a couple weeks ago, we're doing one in the shop today and another tomorrow.

buy the compelte felpro kit.

the right valve cover has to come off.

get a second set of hands going back in. the AC lines and the hard line on the left get in the way and you run the risk of knocking the silicone off the block or smearing the bead trying to wiggle the thing in.

you're probably gonna be looking at a corroded intake manifold around the water p***ages. its a good idea to fix it if its more than just a little fine pitting. a little jb weld, a razor blade and some fine sand paper will take care of that. a new manifold is like $600 my cost...

 

You can get them from the dealer.They stock them as they do about 6-10 of them a week.Its a very common leak.The corners always blow out of them.Also you will need a couple of gals of the orange antifreeze that GM requires.I cant think of the name of it.But I remember there being a tag under the hood somwhere with the name of it.Like mentioned.Do not seperate the black plastic upper part from the intake.remove it all as one piece.Just mark the dizzy on the inside at the rotor and on the shaft at the base of the intake and put it back in the same spot.

 

Happened to me with a '99, I ended up just paying the money. ****s, but figured if I screwed it up they would charge me more

 

just count yourself lucky it's not a 3.1/3.4 v6 intake gasket. i recommend that you replace the spider when you do it because those little *******s go out very frequently. it's very likely that it will need to be replaced anyway, it's been necessary on all that i've done. the new spiders are a much better updated design as well. it's not that difficult of a job to do, the most obnoxious bolt is the very back p***enger side one. never had to remove a valve cover to do one, but i can see where it would help. if you decide you wanna do it, let me know and i can get you the entire service procedure if you'd like.

 

It's Dexcool.....

Harrison....it's JUST a SBC. Sure, there's extra 'stuff' on it, but it's really no big deal....I've done quite a few of 'em. Leave the plastic upper plenum on it.....just unplug the injector plug and lines. The lower half is aluminum....bolts go straight down and not as many as older SBC's...
It shouldn't take more than 2 hrs to change gaskets.
Like 35mastr said, be careful when removing the heater hose from the intake....as this is an area that corrodes and the fittng is cheezy. I replace the fitting with a regular ****** and cut the end off the hose and just use a hose clamp.

 

Thanks for all the info guys. This is exactly what I was needing.

I'm going to do it this weekend & sell the SOB.

JH

 

Really great info here.

The only thing I can add is :
You don`t have to buy your parts at the GM dealer. You should have an O`Reilly`s Auto Parts near you. Buy the FEL-PRO gaskets. If you need the injector spider, they can get it through DORMAN. They will probably have to order it. The coolant is Dex-Cool or any brand "Long-Life" coolant. Use a silicone sealant that says "Sensor Safe" on the package.
The lower intake is just an aluminum intake, torque it like you would an Edelbrock intake.
If you break off the heater hose ******, you can buy a special eaze-out made just for this purpose. You can buy a replacement ****** at O`Reilly`s or as was suggested, replace it with an old style and cut the factory crimped fitting off the heater hose and use a hose clamp.

Good luck !

 

Did the R&R at a local garage that the NAPA boys recommended, had to, the Suburban was in Texas and I was in India. Mine is a '97 and should be good for another 150K.

 

So are they still using this intake setup on the newer motors?

 

You also have to unbolt the ac/ps bracket, make sure all the nuts and studs are out, it has to slide forward to get to the front bolt. I usually wedge something in between to hold it out of place. The blue loctice has a thread sealer in it. The rh valve cover only has to come off if it won't block the intake from coming off, they all don't have to be removed , kinda 50/50 on that one..

 

The newer GEN III engines are completely different, they use a dry manifold. The old Vortec iron motor has been put out to pasture

 

If it the older body style tahoe- the lwr intake gaskets are fairly easy to replace-time consuming but easy..
Remove dist cap and line it with the small#8 stamped on the dist base.you can use a 15/16 socket on the alt bolt and put tension on the belt to help rotate it over(or just bump the engine). small #8 and balancer mark inbetween timing cover notch will be TDC
unclip the harness that gets in your way and hold back with bungie cords
Remove the 16mm(5/8) fuel lines
Remove 13mm compressor bolts and flip it to one side(you dont have to evacute the system)
Remove the driver value cover(helps with getting the first bolt out. loosen the p/s bracket and slide it forward
Buy a new coolant ******(it will probably break, they sell a tap if it does.. spray wd-4o first
Everything is just clean up and Re-install.... Drain the coolant it helps from getting everything in the valley... Change the oil , You dont want coolant getting to those bearings.
Hopes this helps abit..Good luck

 

What is an "injector spider"?

JH

 

The injector spider is under the plastic, upper plenum.....it's just a distribution block, and looks like a "spider".......

FWIW.....I've done a few intake gaskets on these and never removed a V/C......

 

I've done the gasket change on my truck, also, but didn't replace the "spider" or heater hose fitting. Guess I'll keep my fingers crossed.

You'll see, just behind the throttle body, the wiring harness connector and fuel line that go into the plastic part of the intake. That wiring harness controls the 8 injectors. Below that connector there are 8 little tubes that run to each cylinder - feeding the fuel to each one. That ***embly kinda looks like a spider, so I ***ume that's why guys call it that...

Good luck with the project!

Malcolm
**EDIT** What SinisterCustom said, too!

 

It is easy, just like been said already.
I ALWAYS flush out the dexcool and go back to green. Too many corrosion problems with dexcool.

I have a 4.3 V6 to do later today. Easy money........

 

After taking **** off the engine for half a day I found the intake & got it off. Installed the new Fel-Pro gaskets & got most of it slapped back together.

I broke that clip on the heater fitting. I'll get that fixed tomorrow & hope the intake gasket fixed it's problem. Is the blue Loc-***e absolutely necessary? I forgot it.

Every time I work on a "late model" my respect for mechanics is renewed. What a damn chore.

JH

 

the reason that the intake gaskes leak on gm late model's is the long life dex-cool. flush it out go to the green stuff. you want have any more problems with it. we do these at work all the time. you don't need to pull the intake apart. just unhook the wiring lift the hole thing off. if the pot metal heater hose adapter is leaking you can get a new one. but you will all most alwas brack it off in the intake. ther is a tool to pull the brocken chunk out. not hard to get. easy jub. just takes time. 3-4 hours. same the money do it your self. just tork the intake bolts to spec.....

 

Personally I wouldn't use the Dexcool like Duece said. GM has had a long history of problems w/using that coolent and GM has lawsuits out the *** about it because it is believed they knew about the problem but didn't give a rats *** about it...joe

 

the dexcool eats the plastic in the gasket. GM has updated the gaskets a bunch of times. same thing with the 3.1's. its a problem even with some LS motors my pops 01 tahoe. its not so much the gasket's falt its the coolant. if your outa warrenty flush that junk out go to the green stuff.

 

GM sells a replacment gasket for this very common problem. They would leak around the bolt hole openings in the gasket. They now have steal inserts around the holes for the bolts. If you do it yourself your looking at a full eight hour job. I just did mine about a month ago.

 

Get rid of the dexcool. Both my 98 GMC 2500 and 98 Chevy Express van have the same problem. Putting the van off as long as possible, pain in the **** to work on.

 

Thats what I did, finally..
took awhile for me to learn.
Intake gasket, egr valve, alternator, rearend, transmission, engine, etc all went on my 99 (94-98 style) pickup in one year with the truck only showing 100,000miles. I'll never buy another one thats for sure.