Is there any kind of radiator stop-leak that is supposed to be the
Normally I'd just fix the leak (remove radiator & have it repaired,
But this particular leak is in the heater core of a vehicle which
requires removal of the dash to change, which is a HUGE amount of
difficult work, with the considerable likelihood of breaking something
else during the process, etc.... or VERY expensive to have done.
It doesn't drip out onto the floor; it just fogs the windows and gives
an antifreeze smell.
So in this case the old "stop leak"route is sounding pretty good.
Put it this way -- it's the easiest thing to try first.
I have heard claims that stop-leak it will plug stuff it's not
supposed to, etc.
But I am inclined to think that claim is exaggerated or false, since a
hairline crack causing steam buildup on the windows is a thousandth of
an inch wide -- which is what the stop-leak is forumlated to address --
is infinitely smaller than the passages in any radiator or heater core.
I know there are several different types of the stuff.
There's the silver granulated stuff, the goop with the little pellets
that look like rabbit turds in it, and I think there is some that is
basically just a liquid of some kind, maybe kind of thick or whatever.
Which kind is best for what I am doing?
This has piqued my curiousity. For example, does the stuff have to
get hot to work? Does it have to be under pressure -- so that the
coolant starts to escape through the fracture -- in order to plug it?
I saw some demo's on youtube with mfgr's simply pouring some into a
leaking can and the leak stops. I thought, what about when the metal
gets hot and the fracture expands, and under pressure now...
Please don't give me any crap about this jury-rigging fix -- you all
have done stuff like this too, or tried to LOL
Thx in advance.
On Mon, 10 Oct 2011 20:44:58 -0700, email@example.com (James
When I had radiator leaks long ago the silver granulated stuff worked
every time for small leaks.
Never had the cars long enough to know if there were bad side effects,
but drove some at least for a couple years later.
Years later I wouldn't use stopleak, and replaced a couple radiators
and a heater core, but it didn't require removing the dash.
In your situation I'd try the stopleak just as you are.
Go with the GM tablets and see if that works. Any GM dealer has them.
I bought a '90 Corsica in '98 and read they sometimes leak at the head
gasket. I saw rust stains in a corner of a head, so when I did my
initial new-old-car hoses/belt and fluid change I put the GM tablets
in. Broke them up a bit first.
Put about 60k all city miles on after that with no problems.
About 4 years ago I added them to my '97 Lumina 3.1 when I became
aware of the LIM gasket problems on that engine.
No problems in about 60k miles since. I put new "improved" LIM
gaskets in earlier this year, not wanting to push my luck.
I can tell you the tablets scummed up my radiator fill neck and the
overflow tank, but it wipes off fairly easily.
I saw no sludge or contamination in the manifold and head water
passages when I did the LIM gaskets.
Probably changes state when it's exposed to oxygen, but you can look
Also believe the GM tablets are plant material, ground up ginger root
and nut shells.
Reason I didn't hesitate using the tablets is I read GM put them in
some of their new cars, maybe Vettes and Caddys.
Looks like they're a variety of Bar's stopleak.
I just get them from a GM dealer.
Keep in mind I don't know if they ever stopped a leak, just that
they're probably the safest bet.
If they don't stop your core from leaking, flush it out and try the
silver granulated powder.
One thing I don't know or can't recall from the old days is whether
the leak comes back if you flush your coolant, so you have to put some
stopleak back in.
And we learned they are usually short term fixes and unreliable. Given the
amount of work and cost to repair the heater core, I may try it anyway.
Worst case is you may lose the cost of the product, but if you don't overdo
it, most likely.
It may be just a cheap to buy another car than have the heater core
Ed said, "And we learned they are usually short term fixes and
unreliable. Given the amount of work and cost to repair the heater core,
I may try it anyway. Worst case is you may lose the cost of the product,
but if you don't overdo it, most likely.
It may be just a cheap to buy another car than have the heater core
Ed, I would venture to say a lot of people DO consider just getting
rid of the car rather than replace a heater core. Some folks wouldn't
really have a choice.
That's what really galls me about this: the expense and difficulty of
repairing something that goes out THAT commonly.
I would hate to be the service manager at the dealership who has to
tell customers such a routine thing is so expensive, the cost probably
approaching four figures to fix.
No wonder people get so pissed off, don't trust mechanics, vow to
never again buy GM , kids don't want to enter the automotive field etc.
What a GLARING design flaw.
And I wouldn't be too happy if I was a tech working at the dealership
-- and had to go through all that contortionist routine every few days
when someone came in with one of the zillion Blazers out there needing a
heater core. I don't care how much the job paid, you'd really be
I have been reading on the internet in forums where the thread is
about peoples' experience with stop-leak, and there actually is a fair
amount of people who used it and then drove the car for years afterward
and it still held. I'm not hanging my hat on that of course, but you
know what I mean. If the stuff was totally worthless and NEVER really
worked, there wouldn't be a dozen different kinds out there.
But I STILL haven't decided which kind to go with until I have more
answers.... I look at it as that I have one chance. According to a
comparo I found on the internet, the type that Bar's leaks is was
described as "the only type even close to being permanent." I'll post
that article if I can find it again. Thx.
I get my oil changes done at a local radiator repair shop. Bill has told me
a few horror stories. In many cases, the heater core has to be replaced,
not repaired. On certain models of Fords, the book time for the job is 8
hours. Dealership shop rates are $65 to $100, plus parts.
Used to be, it was a 15 minutes job to pull it out, a shop would fix the
leak and another 15 minutes to put it back. I remember putting cardboard to
cover the firewall hole on my Pontiac until I got the core back. .
I also wonder why heater cores go out so commonly anyway.
Compare it to the car's radiator, which often lasts the life of the
car, even though it's spent years getting blasting at 70 mph into
pebbles, bugs, sticks, rain, snow, and minus-20 degree air etc.
By contrast, the heater core is enclosed in a box, inside the
passenger compartment, untouched by anything, ever -- and they go bad
all the time. Why is that?
On Wed, 12 Oct 2011 06:23:52 -0700, firstname.lastname@example.org (James
A/C condensers offer some protection for radiators.
Personally, I've only had 2 radiators spring a leak, probably from
pebble dings, and both had no A/C condenser in front of them.
One other when I dropped a wrench, which bounced from grill to
radiator, no condenser on that one either.
Only one OEM heater core, and that from a plastic inlet or outlet
tube. '85 Cavilier.
The replacement I put in had copper tubes.
Only reason a heater core should leak is shit quality.
Never saw mention of your make/model.
Sometimes you can find methods to change out things that work better
than shop manuals.
Pulling a dash isn't as hard as many suppose.
If it's 8 hours @ $100 per at the dealer, and it takes you 16 or 20
hours, you're still making/saving good money.
All comes down to tolerance of physic pain.
Too painful for me, but my kid just replaced the dash on his
Bonneville, and loved almost every minute of it.
The radiator is out in the elements BUT it is designed to handle that.
The fins are more open, the core is thicker material, and the rain
actually helps by keeping the unit cleaner. They also dry off real quick
when they get wet and usually they are very well mounted so the flex and
expansion doesn't bother them as much
The heater core on the other hand is a MUCH denser unit, fins are
tighter, the moisture and crud just lay on it and cause rot. The way
that air is ducted to it also means that water/snow can get in there and
cause problems. Even if the drain works perfect there are areas where
the weather stripping retains moisture and. The core also doesn't dry
out real well. Many newer vehicles shut off coolant to the cores so they
don't heat up and dry out, this is also why you get the mold smell with
newer vehicles. The moisture allows mold growth.
Want to make that heater core last a LOT longer?
When you take the car out for a drive, on your return trip turn the heat
on full blast for the last 5 minutes or so. This will dry the core and
the ductwork. Once a year crawl underneath and clean out the drains for
the core. This is REAL important if you have pine trees or other needle
type foliage where you park. That crud will clog the drain real fast.
When you run the A/C during the summer it is also a good idea to run the
heat for the last few minutes to dry out that core as well.
PeterD said, "Go to a GM dealer's part department, and tell them you
want the GM stop leak. "
Thx for the reply.
Is that the same stuff as those tablets I've heard about ? Or
Mind if I ask why you'd recommend that over the other products
available out there? TIA.
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