'99 Suburban water leak (major)

[Doober]

It's my mom's...

she asked me if I could take it into town & fill it up. No problem. Got to the opposite side of town (maybe 3-4 miles), the gas station I was headin' for was closed. Heading back, halfway through town I lost heat, so I had a feeling something was amiss. Sure enough, when I pulled into speedway the thing had some steam comin' from under the hood. I knew it was barely up to operating temparature so I opened it, and found water on the upper intake (I'm assuming it was thrown up there, see below). Got some antifreeze to put in to make the drive back, and it started pouring out from somewhere around the front of the block/water pump area. The pump is maybe 1 year old. Got it back home, but I haven't touched it yet. Anyone have any ideas before I start tearing the thing apart (as in any common failures I should look for)?

 

[Doober]

Couldn't wait... not a bit tired so I started tearing into it. Found out with about 99% certainty that it's the intake gasket :x At least it wasn't something expensive :lol: I guess this is what they were talking about them doing after they aged eh? So far the one on the 'Bu hasn't done it, but now I know what to look out for...

Possible pics

 

[BryanH]

Its a fairly common problem with those, make sure you clean the bolt threads good and torque to spec, its a low clamp load due to the plastic carrier silicone rubber gasket, i cant remem the spec off the top of my head, GM has redesigned those gaskets if you choose to use a OEM gasket, you may need a scan tool to reset the distributor knock retard to spec, but you can get it close by marking everything(dist to intake, rotor to distributor)

 

[racecar77]

I've done several intake gaskets on those as well. They rot around the water jacket. Make sure you check the disconnect fitting in the intake for the heater hose. They are like a pot metal/aluminum and have a rubber ring in the bottom. They also corrode and when you unscrew it to replace it, they usually break off. You can then peel out the remnants with a screwdriver and small hammer, works better than an easy-out. I would pressure check the cooling system first and make sure where the leak is. Good luck, Lee

 

[dwkohout]

I have replace hundreds of plastic intake gaskets at work. This felpro set was installed in my buddies 400 with vortecs I built for him in 03. Sucked the silicon bead right into #2 cylinder. Thought my buddies 400 cracked a head or block. When I put his 400 back together I have Felpro MS 98000T to replace the plastic gaskets. They are a viton type covered steel gasket.

 

[Doober]

Yeah, I have those plastic ones on the 'Bu right now #-o I'll be replacing them with the 98000Ts when I do the rings (so far haven't had any cooling/running issues). Here's where I am on the 'Burb:

The underside of the throttle body had lots of carbon on it (plenum is pretty well caked too)

I've read about this fitting in another thread and the breakage issues, but we know that wasn't leaking. You can see the silicone where it's been apart once before, probably won't be attempting to take it out since it doesn't leak (unless I can't get a new clip that held the line in place).

It blew out here (don't know about the other 3 water passages), you could see water come out when squeezing the radiator hose:

The truck has about 178,000 miles on it hopefully it lasts a while longer, at least until this country can get back on its feet money-wise. Then it may come out for a replacement or rebuild. We'll be gettin' the 98000T gaskets tomorrow (I have the plenum/injector housing/throttle body gaskets from my motor build that I could use should we take the plenum off)... expensive buggers ($60), but neither of us would want to have to tear back into this sucker to fix it again :roll:

 

[dwkohout]

I've read about this fitting in another thread and the breakage issues, but we know that wasn't leaking. You can see the silicone where it's been apart once before, probably won't be attempting to take it out since it doesn't leak (unless I can't get a new clip that held the line in place).

You are in luck cause the pot metal quick connect that truck came with has been replaced with steel. I recall yrs ago replacing tons of broken off quick connects on 3.1 luminas/cutlass/regal/etc without removing the intake. I had a system of tools to ream out the broken off part and clean the rest out with pipe tap.

 

[ILLEGAL REGAL]

put a good felpro gasket on it.. had one do the same on my Tahoe and they did it under warranty around 60k and tried to get them to use felpro but they said they couldn't.

 

[Doober]

That's good to know DW. Illegal, we got the $60 Fel Pros today It seems to have a weak (not quite collapsed) lifter (at least it bleeds down faster than the others, but pumps right back up with pressure), my dad wants to replace the lifters, but is not quite sure he wants to spend the $ on it just yet (may, may not, still up in the air). I was surprised I was able to find the plastic fitting for the rear heater hose in the HELP! section at the parts store as well, which was nice.

 

[Doober]

Nasty, nasty, nasty! Someone didn't take care of it That & the intake gasket's probably been fried for some time.

Took the spider out, gonna wash it off & the rocker covers out, doing the intake by hand (concerns of sensors, injectors, etc.), and we're gonna run some Seafoam through it. I'll try to remember to get a pic of the sludge in the lifter valley. We're both a little concerned if we try to clean the valley out it'll cause more issues than it currently has, and we just don't have the $ for it. Maybe when things pick up (aka the old house sells, went up for sale just after the economy started takin' a @$^#) it'll come out for a rebuild, but right now it has to stay somewhat drivable. It blows up, we'll manage