Sorry for bringing up another coolant related issue but the collective
wisdom found in this NG helped me out before, so it might again.
I've had the leaking heater control water walve replaced a couple weeks
ago in my '94 Accord and I thought that may have fixed the slowly
depleting coolant issue I was experiencing. I also noticed some slick
condensation inside the windshield when the heat was turned on and I was
hoping it was only due to the leaking water valve, not a leak in the
heater core. Well, after the valve was replaced, the condensation and
cooland deplation was reduced, though not entirely. But I thought I
could live with it till the next next heating season. So I was quite
surprised today when suddenly the inside condensation returned but this
time without the heater being turned on. The air was dry outside, with
clear skies. I even tried to dry the inside air with the A/C on with no
avail. The condensation became quite severe and felt slick, so it must
have been due to coolant leak, probably in the heater core. What I don't
understand though how that could happen if the water valve was closed. I
assumed that coolant got into the heater core only when the valve was
open. Could the source of this condensation be somewhere else than the
I sure would appreciate your thoughts on this.
Not necessarily...This happened to me on a Series IIA LandRover...One day,
out of the blue, I got a blast of "steam" inside the cab and a sticky,
slick film on my windshield...About three days prior, I had replaced the
input hose to the heater (split but not leaking)...When I installed the new
hose, I did not get a good seal at the heater core. As you have been
working with your heater, I would check for leaking at the top heater hose
which would let coolant leak into the heater core enclosure...May or may
not be but would be worth a look, IMHO...DaveD
i'm so sorry. when you were bleating about replacing a hose that
stopped a leak inside the cabin, i ass-umed that you didn't have a
vehicle that drained through the firewall or have a dysfunctional blower
design that would convey outside fluids inside. my mistake.
oh dear. but i guess that if landrover weenies knew about the <sarc>
thing, they'd have a hard time showing themselves in public because
they'd understand what other people were really saying about them.
have a nice day!
Water glass sealant? You mean something that you pour into the coolant?
I have not heard of that particular one yet but I've been always
ambivalent with such temporary fixes unless out somewhere on the road
and I need to get home. I feel some of that stuff can do more damage on
the long run than it's worth to use close at home. But you may know some
newer stuff for which my old notions might be out of date. Is this water
glass one of them?
so i'm told. to be honest, i've not had occasion to use it myself, and
i'm a "repair it properly" person anyway, but others swear by it. and
it does work. don't pout it into the coolant though - drain and flush
with water first.
commercially marketed for auto use, there's a brand called "blue devil"
or something like that. but it'll cost $60. if you buy "sodium
silicate solution", it'll cost you just over 1/10th of that.
anyway, check it out. it might work. if not, then you're out a few
more bucks, but not as much as a new core will set you back.
Well, I've been googling this water glass subject a bit and its use for
leak sealing does seem to have quite a following, even for head gasket
leaks. On the other hand there is also a lot of caution around what
damage might be caused by its use, like in water pumps. So I am not
quite sold on it. For starters, I am not keen on the idea of first
flushing the system out with clean water bacause it's not that easy to
get rid off all the coolant from the system without some special
equipment designed just for that purpose. For instance, looking at the
Service Manual I've got, I noticed in the specs that the total cooling
system capacity, incl. heater and reservoir, is 7.3 US qts. Then, in the
Refill and Bleeding section it specifies Engine Coolant Refill Capacity
(incl. reservoir): 5.6 US qt. So where is the 1.7 qt difference? I
figure that much cannot be drained out, right? So flushing that out also
is not something an average joe can easily do in his garage.
But I found one post that contained a pretty cleaver idea that seemed to
me also the safest in using that water glass solution to fix a heater
core leak. He disconnected the heater core from the rest of the cooling
system and used one of those hand drill operated small pumps between the
two hose connections of the core to circulate water within the heater
core itself. The circulating water already had that water glass added to
it. The poster also wrote that he used a heat gun to heat the core in
the process to keep the water hot inside for the water glass do its
bonding. I just don't know how he could have heated the core with a heat
gun without taking out the core in the first place. But that would then
defeat the purpose of the quick fix, right? Go figure ... But perhaps
just using preheated water would also do the job, who knows? Anyway,
after a few minutes of doing that closed loop circulation, the guy
drained the core, reconnected it to the system and refilled it with
antifreeze. That stopped his leak for good, according to him.
I haven't decided on what I'm going to do, but I kinda' like the above
idea because it avoids the potential problems water glass could cause
elsewhere in the system.
it's a good idea if you can get at the core that way. but on the honda,
to clear enough stuff out of the way to get the heat to it, you may as
well take it out in the first place.
as for replacing the water pump, i think that might be a risk, but
frankly, it's a lot cheaper and easier to replace that than the core.
if i had a drill operated pump, some old copper pipe [where i could
apply the heat], and the inclination, i'd isolate the heater core and
give this method a shot.
That was my thought, too. I just don't understand why the can't design
cars with easily accessible heater cores. I don't think it's a rocket
Coming up with a repair kit for exactly this purpose could probably sell
pretty well. A small in-line boyler with a heater element that could be
connected to the heater core coolant line and the drill operated pump.
Mechanics might probably want to buy it. I was also thinking of a
temporary bypass of the heater core that could come handy in an
emergency. In my case I could now probably get by without a heater till
fall. That would give me enough time to come up with the best permananet
fix for my situation. Too bad that water valve is not designed to force
a complete coolant bypass from the heater core.
As it is now, I think I'll just bite the bullet and have the core
replaced with a new OEM core from Majestic Honda. That costs less than
half what the local dealers charge and then I'd also have to pay almost
10% sales tax on top of that. I'll sooth my budget-pain by telling
myself that my spending will at least provide a badly needed economic
stimulus. ;-) There, I already feel better.
yes and no. with quality initial components and scheduled antifreeze
changes, they're usually exceptionally reliable and thus, the reasoning
goes, it's not necessary to change them. however, if ever there is a
need to change, they're the very devil and i agree, it seems retarded to
not make them in some way accessible without total dismemberment of the
dash. afterall, the a/c is designed that way - so should be the heater.
i was going to suggest that, but frankly, it's a kludge and it doesn't
fix anything. it's really just a "get you home" emergency measure.
it's for a reason. they were like that in the old days, but after
months and months of zero circulation, cores would clog up, sediment,
and even gel completely. a little circulation fixes all that.
OK, I think the YES here wins out over the NO. ;-)
Oh, I didn't think of that, but makes sense. In any case, my new
mechanic suggested to bring my own heater core because he could not get
an OEM core for anything close to the price I could get it online. He
doesn't seem to care about making extra money on part markup. I trust
this guy because I know him socially and his customers swear by him. He
is also a certified ASE technician. So I already placed the order and I
hope it gets delivered before the week is over.
I almost forgot to mention the issue of grounding the heater core to
avoid electrolysis. I've heard both pro and contra arguments on that.
Frankly, I don't even think Honda heater cores have a place reserved
for attaching grounding wire and I don't see it mentioned in the Service
Manual. What do you guys know about this?
I am aware of several Ford sevice bulletins on this subject (seems to be a
common complaint against some Fords, although not a problem I've had
recently). They are not directly applicable to a Honda, but they may be of
I thought I could remember an older Ford TSB that mentioned grounduing the
heater core to combat repeat failures, but the newer TSB is pretty clear in
stating this is not recommended.
I've bounced this off one of the mechanics I know socially (too busy to
be my own mechanic!) and this is what he wrote when I asked for his
comments on the electrolysis issue and copper vs. aluminum cores:
"The only comment is that is all bullshit, sometimes theory is different
than reality, have done hundreds of heater cores,not one has gone bad.
This is after the customer had replaced numerous cores. Interesting that
before they went to aluminum for cost and weight savings,they used brass
and very rarely went bad, when they did, it was 30 years down the road!"
If there is that much disagreement among technicians, how is the average
car owner to know the right way?
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