1998 Tahoe 4X4
Coolant leak which appears to be at the back of the engine on Passenger
side.( slow drip at bell housing and transmission pan has lots of dropplets
all over it.)
Has not been abused or overheated.
This problem started last weekend.
I started checking from the front to the rear of the engine.
Water pump, hoses all inspected good no leaks.
Replaced the fitting for the heater to the manifold, No help.
I am slowly tearing down more extenal stuff on top of the engine to pinpoint
Any problems with this model ?
Is it possible the intake manifold is leaking at the back corner.? ( I sure
hope not. )
Truck was purchased new and has not had any cooling system work done except
the water pump and hoses @ 100,000 miles.
Always has had Dexcool in it.
Look forward to all replies.
I would be willing to bet anything that it's the intake gasket. An endemic
problem on all of these 5.7's. Happened to my '94 K1500 Suburban at about
100,000. Since it was winter (Alberta, -25F) and I was pressed for time and
heated garage space, the dealer did it. About $500 or so if memory serves
me, but I had them do a chemical rad flush and coolant change at the same
time, as well as a required oil/filter change for coolant contaminants. This
was about 4 years back, and I was told the new style intake gasket was not
prone to the problem.
The problem is kinda cronic on Vortec 350's because there is only 8
bolts holding intake on vs 12 with TBI and carb 350's. GM skipped the
middle bolts on VorTec which leads to intake wanting to creep around a
bit more from heating and cooling. GM redesign the intake gasket for
it in late 2005. I had this gasket fail twice on my 2000 K3500 with a
5.7 in it. Once at about 30K mile under warranty and again at around
38K out of warranty. GM fixed it for free second time last year and
"promised" it would not leak again. Using a lower pressure radiator
cap helps extend seal life too. (I do now since second seal failure)
The gaskets fail because the aluminum lower intake manifold
expands at a different rate that the cast iron cylinder heads,
the OEM gasket design is so poorly designed that it can not
withstand the shearing that occurs between the manifold and the
head. Better designed gaskets do not fail ruling out your
'missing bolts' theory. Also, were the failures due to 'missing
bolts' it would stand to reason that the failure point would
occur in the area of the lower manifold where the bolts were
deleted, since this doesn't happen, further evidence that your
theory is nothing more than armchair supposition.
Except that the leaks do not occur where "GM skipped the middle
bolts." Further, the 4.3 Vortec engine also uses 8 bolts to
mount the lower intake manifold which -should- result in a more
secure and rigid attachment, yet the gaskets on the 4.3 fail at
the same interval and same mileage as do the V-8 engines.
Came up a little broke did ya?
Hilarious! The great Snoman, knower and seer of all things can
not keep his own truck from puking coolant without resorting to
The "fix" is a more durable gasket (not OEM), not more bolts.
More bolts would only result in the badly designed OEM gasket
tearing in more places than they already do.
No armchairing at all like you do all the time. Sure it has a
different expansion rate but because it is not clamped in center it is
going to tend to expand more in center (bow out a bit) and dig in a
bit on ends and usually they leak on ends after many cycles. If it was
better clamped it would likely hold/seal better because intake would
For reasons stated above though it likely escapes you
Were do you get this. They told me that it should not have failed
again and that a new style replacement was avaible. GM in Detriot
authorized the free fix it and even gave me a nice rental car too. If
you want to pay for something that you should not have to knock
Typical ignorant troll comment. Been runing lower pressure cap on many
cars for many year and never had one overheat or puke as you put it.
(heck, they do not even get warm ever) Been up Pike Peak twice with
one on my old Burb and been through 10% plus to with A/C and it has
never exceeded 210 in 18 years and 180K plus miles. This vehicle still
has original hoses and they look like new and it has never leaked.
Plus if you were ever to get a leak it would be a LOT less explosive
with a low pressure cap. One more thing that likely escapes your troll
brain, the high pressure cap it there to help minimize gas bub barrier
that forms on a hot part when water or a lower mixture ratio coolant
contacts it which retards heat transfer (this is why some car can pop
off after shut done and BTW, temp sensor reads coolant not actual
block temp) I have been using 70/30 for years with increases heat
transfer efficency This is why there is a myth that they run cooler
with water because glycol transfer heat better from parts and has a a
much higher heat content too (take more heat to heat same amount of
glycol as water) and glycol weighs more too. The higher ratio raises
boiling point so less pressure is needed. One more thing, if you ran
pure Propylene Glycol (non toxic antifreeze) you would not even need a
pressure cap because it freezes around 90 below and boils around 345F
at sealevel pressure. (They likely do not teach physics in troll
scholl so I may be wasting my breath with you.
Your lack of physics knowledge really shows. Extra bolts wouls help
some and the 5.7 OEM gasket was completly redesigned in late 05 and
the 4.3's a littel before that so while there was problem with past
gasket, they may have it fixed now. (no doubt why they offer to fix
mine for free because there has been problems with them.
"No armchairing?" That's an absolute laugh coming from someone
who had someone else replace the gaskets on his truck.
It's going to expand more in the center, eh?
As supported by the driveability problems that arise [not].
Too bad your theory isn't supported by the way the gaskets fail
on the Buick 3800 engines.
As you probably [don't] know, the Buick 3800 uses 12 bolts to
fasten the lower intake manifold and the coolant passages are
near the center of the cylinder head, yet the gaskets scrub and
tear the same as the Chevy engines.
So much for your "expands more in the center" and "digs in a bit
on the ends" theory.
For reasons stated above, your theory is not only in error, it's
Know why it's knee-jerk?
Because all you've seen of any of this is the outside of the
engine, all you've seen is some bolts that GM used to use aren't
You might become a little more enlightened if these engines were
as transparent as you are.
Are you saying that GM called you and offered to replace the
gaskets a second time just because they're nice guys?
You must have pitched a royal fit.
The truck was out of warranty, "should not have to" translates to
pissing, moaning, whining.
Nice back pedal. I'll go with "I do now since second seal
You put explosives in your cooling system?
The cavitation damage to your engine is probably worthy of the
Gee, thanks for sharing that.
All bullshit, but I was wondering how long it was going to be
before you hopped on your 'coolant' soapbox.
So, if pure Propylene Glycol is so good, why aren't you using it?
I never claimed to be a physicist, but I do know first hand what
the engineers at the OEM gasket supplier to GM have to say about
why these gaskets fail and it certainly doesn't jive with
anything you're saying.
"Completely redesigned?" You DO love to show your ignorance,
Redesigned by another vendor who sadly isn't supplying GM -or-
their dealerships with warranty parts.
Yeah, it's fixed, they redesigned the engine with a dry manifold.
Yours however will fail again and each time it does, coolant is
migrating into the crankcase washing the main, rod and camshaft
I was going to replace mine myself but if they are going to do it for
free and warrant it I do not have ego issues about it.
Nothing neat about it (your lack of physics shows, a Troll short
coming I guess) The is more mass in center and aluminum expands more
with heat so center will "grow" more on intake side and stress will
build up and it can only bow out to relieve stress which forces ends
in a bit and that "worries" gasket on end.
And why? A few thousands of shift is likely not enough to beak seal in
middle and there is no pressurized coolant in middle to "test" it but
it will take a toll on gasket at ends over time. (again I know
armchair Trolls have a lot of trouble with physics).
No my theory is sound. The fail a lot more and sooner on SB V6's and
V8's. (especailly V8's) Another problem is coolant. Mazada recognized
in 70's when they first cam out with rotary that 50/50 anything is not
good on a mixed alloy engine because of the galvanic reaction setup by
disimular metals can take a toll on gaskets between them too. GM's
Dexi was a attempt to stay with 50/50 to save fleet coolant costs but
is has not gone as planned. (Trolls never look past their nose or at
biggers picture of causes and effects)
I guess I have to keep it simple for a simple minded Troll like you
because you forget what you have read 5 seconds ago.
No, I contacted GM myself and they offered to fix it for free. Dealer
I bought truck at suggested it because they are troublesome. GM in
michigan made sure latest gasket was used and replaced everything
related to it even Tstat and even asked for old gaskets back to
verify reason for failure. I did not have to twist their arm and they
even offer 1 year free maintainance too (which I never used)
Nope, see I am not a Troll like you and I have bought GM products for
years (likley before you were born and surely before you even though
of driving) and they knew it and that I was not a whiner like you
Maybe if you are a hot headed Troll like you. It was VERY pleasant. No
real fuss at all. GM called me on phone to set it up after I sent them
a query. See you are used to acting like a child to try to get your
way but it is not the norm for many nor is it even needed a lot of
time if you are a credible client unlike you.
Yes it failed agin BUT, it was minor and did not require instant
repair with cap. It was loossing a few oz's a week or so at most and
over a period of a few months I saw that it was down a little. Had it
been a stock cap, it would have lost a lot more.
That is dismiss it when you cannot understand it. Typical Troll.
Another Troll answer, 15 or 16 PSI coolant can be a a lot more
"explosive" (meaning force or violence of leakage) in a hot engine
leak when is flashes to steam than with a lower pressure cap but you
lack of physics understanding painfully show through as you try to CYA
Where did I say "cavitation" at Troll??? Again you have not studies
heat transfer for hot surface to water nor surface tension or water vs
glycol nor heat density of them. But as you usually do, if you do not
understand it (which is a lot of things too) you attack it but in
doing so you show how little you really know.
If it recorded block temp you would see it was coolant with higher
glycol content than lower content.
Of course a Troll like you would call it BS because you have NO
knopwledge of physics, surface tensions or liquid, energy density
(amount of heat it can absorb) and so on. So sad!!!!
It is expensive and hard to find. It is used in Artic conditions like
at the poles. If I ever find a good cheap source for it I will switch
to it untill them I will run between 70/30 and 80/20 (the range I
shoot for) with "toxic" anitfreeze. BTW, I do have several gallons of
Propylene Glycol in my boiler for house (about 10 gallons of so) to
provided freeze protection fo hot water heat system if heat fails in
extreme cold some winter (it never has). Nice thing about using glycol
is that even in lower constentations (warmer freeze points) water does
not freze solid and expand the same way and it will not easily split
pipes (or engines) but they may have not taught you that in troll
If you do not understand physics you should not debate something that
you do not understand (but if you only debated what you did fully
understand you would have nothing to debate)
Sure GM out sourced it but they speced/requested design change.
I am not concerned because both leaks had no trace of coolent in
crankcase. BTW, the "problem" with antifreeze in crankcase is that it
does not wash the bearing but they is can combine with oil under heat
and presuure and create a frictional cohesive that can damage and wear
out bearing far quicker than plain water mixed oil can. They also make
a specail flush to remove traces of antifreeze from crankcase and I
have used a it a few times. (I bet that is not in your Troll manual
Why, I have not contacted them about anything else though I should off
the way my 2000 eats brake lines were they cross frame near exhaust
manifold, I have replaced myself all three of them as they rusted
badly there and no where else. Engine oil coolant line are poor
quality too and they tend to rust out as well.
You don't have "ego issues?"
Dude, that's all you've got. Why else would you keep coming here
Here's a picture of the lower manifold;
Even a blind man can see that what you claim is bullshit.
Also, please explain how bolts in the vertical plane can stop
movement in the lateral plane.
IOWs, how do fasteners oriented as I-I control movement <->
Well, is it a "few thousandths" or "bow out a bit" due to the
"more mass in the center?"
Are you that stone stupid that you can't see your own
So, on planet Snoman, things bow out in the middle due to more
mass but they only move a few thousandths. You are claiming two
things that can't occur mutually at the same spot on the engine.
Now you're claiming that galvanic corrosion causes plastic intake
manifold gaskets to fail.
or, maybe you thought that would be a good place to insert some
incoherent gibberish. <shrug>
GM implemented a coolant that cost twice as much as conventional
green coolant to save fleets money?
That's a good one.
The only person who has forgotten what they read (or posted) 5
seconds ago is you bozo.
IOWs, you called them and complained about a failure that was out
Of course they did, you were out of warranty.
They weren't going to do it until they knew they'd get paid.
They wouldn't even call on your behalf you fool.
Seen it many times, replace everything and anything related to
make sure the pain in the ass stays gone.
IOWs, they went in the warranty bin in case there was an audit.
Standard operating procedure.
There ya go, contradicting yourself again.
Why wouldn't you take their free maintenance since it was free?
That was the determining factor when it came to replacing the
gaskets wasn't it?
Unlike you, I know better than to buy a truck riddled with known
Okay, I'll take that bet; what ear did you buy your first GM
(it's put up or shut up time)
No doubt it was pleasant, you dodged having to work on an engine
that obviously scares the bejesus out of you.
After you checked to see what freebies you could get out of
I don't -need- to get my way, I am perfectly capable of repairing
my own vehicles.
Another contradiction there Snofool. "I do now since second
failure" doesn't jive with your claims in the above paragraph.
Me thinks you're nothing but a common garden variety story teller.
I'm not dismissing anything. What does your shitbox 89 Suburban
have to do with leaking intake manifold gaskets on a 98 Tahoe?
Has it ever occurred to you that these side tracks of yours make
you look like an even bigger buffoon than that which is being
documented and cataloged by others?
Here's news for ya; so can filling your AC system with
hydrocarbon refrigerants. Another contradiction.
Why would it flash to steam, you've claimed earlier that your
coolant doesn't get hot enough for that to happen.
YA (yet another) contradiction.
You didn't, I did. Pity the poor bastard that gets stuck with
that piece of crap.
So, you think 16 pound radiator caps are just a great big
conspiracy to take you out, eh?
WTF is THAT gibberish?
I sure as hell hope I have no knopwledge of physics. I hear that
those knopwledges are mighty noisey and hard to tame.
I should have pointed out here that the correct numbers for
propylene glycol are -76* (freezing point) and 370* (boiling
Looks like they don't teach physics at dumb fuck school either.
So expensive and hard to find that it's a common food additive.
Yeah dumbass, because it's less likely to poison the wildlife if
there is a spill, not because it's a better coolant.
Again, cheap is good yet you turned down free maintenance.
You have me confused with someone who gives a shit.
Toothpaste has propylene glycol in it, you should fill your
boiler with toothpaste.
Hey dipstick, I didn't say I didn't understand physics, I said I
never claimed to -be- a physicist, but don't let that stop you
from further projections.
No, you need to show, describe, prove this complete redesign by
Someone else did a complete redesign you numbskull.
Now show evidence of GMs complete redesign.
(maybe it's over there>> next to the recall on Triton spark plugs
you claimed in another *group)
They would have no way of knowing that short of sending the oil
out to be analyzed and GM doesn't pay for oil analysis unless
it's going to court.
Who is "they" and what is the name of this product?
All known common problems on GM trucks for years and yet you were
stupid enough to buy one anyway.
Yup, you da expurt on physics awlright.
I'll second it, intake manifold gasket leak.
Did my '99 Yukon at 90k miles. Not too bad a job if your a motorhead. Don't
forget to get a new "quick release" heater hose connector before you start.
It's the connector at the front pass. side of the manifold for the heater
hose. It will snap right off when you go to remove the hose. It's cheap an
was in stock at my local dealer.
It's made of pot metal and will chip out of the manifold easily when you
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