94 Civic: coolant drain/flush and thermostat

I recently had a stuck thermostat at an inopportune time, and had to get
whatever CarQuest supplied the mechanic instead of OEM as I had figured
to put in when I replaced the coolant later this summer. I still have to
replace the coolant and bleed the system, which wasn't done during
thermostat replacement.

I never had a problem with OEM thermostats in American cars. Any
particular reason to replace the new aftermarket with OEM here, when I
change the coolant? I wouldn't mind a thermostat that stuck open when it
failed instead of closed, actually, but since they don't fail all that
much I suppose it isn't really worth it.

Also, what's the best way to flush out the crud? There's some
nasty-looking green **** in there now and I have no idea what was put in
last--i.e., whether it was the right stuff for an aluminum block. On my
85 Pontiac (large engine, lots of room under the hood) I'd just use a
flush kit that allowed me to hook up a garden hose to the coolant
system. Would drain the old coolant, then refill, run the engine a few
minutes to get things circulating, then drain again. I suppose if I
wanted to get water contaminants out after that I could run distilled
water through after that and drain again. Thoughts?

"Abeness" > wrote
> I recently had a stuck thermostat at an inopportune time, and had to get
> whatever CarQuest supplied the mechanic instead of OEM as I had figured
> to put in when I replaced the coolant later this summer. I still have to
> replace the coolant and bleed the system, which wasn't done during
> thermostat replacement.
>
> I never had a problem with OEM thermostats in American cars. Any
> particular reason to replace the new aftermarket with OEM here, when I
> change the coolant? I wouldn't mind a thermostat that stuck open when it
> failed instead of closed, actually, but since they don't fail all that
> much I suppose it isn't really worth it.

I paid about $18 last year for an OEM thermostat for my 1991 Civic. My
recollection is folks here said the OEM was worth it. $18 seems cheap
enough, compared to IIRC something like $10-$12 for non-OEM.

> Also, what's the best way to flush out the crud? There's some
> nasty-looking green **** in there now and I have no idea what was put in
> last--i.e., whether it was the right stuff for an aluminum block.

I would dump this and flush the engine block and lines immediately. From
reports here and one of my own experiences, the conventional green stuff
will greatly shorten your Civic's water pump's life. The good news, though,
is that, if your 94 Civic is like my 91 Civic, it should be easy to give a
pretty thorough flush. (It's more of a fill and drain as opposed to flush.)
The reason it should be easy is that, by (1) opening the petcock on the
radiator; (2) removing the engine block coolant drain bolt; and (3) emptying
the reservoir, all coolant should come out of the system. I did careful
measurements of what came out of (1) and (2) and they matched exactly what
the manual stated should be the capacity for the system.

Here are my hints on the job. The hardest part will likely be removing the
engine drain bolt. But even that was very easy on my car this time. Others
have some horror stories on this, though.

-- Tips on Draining, Flushing, and Filling 91 Civic Radiator/Coolant
System ----
Engine block drain bolt:
The car's front hung out of the garage a little, so I had plenty of
sunlight to see as well as possible the engine block drain bolt. The only
interference I removed was the air intake duct (two bolts) and the O2
sensor wire from its bracket (just laid it aside without disconnecting
anything electrically). I used a 19 mm 8-faced long socket and an 18-inch
breaker bar on the drain bolt. It wasn't going to come free easily with
anything with a shorter handle; I tried my ratchet. I
applied force but not so much that I thought I needed to lay pillows on the
car, to break my fall, in an extreme case. Thought I felt it break loose.
Son of a gun, it had loosened. By my records, the last time I had it off was
12 years ago.

For other folks, I suggest maybe spraying down the drain bolt head with PB
Blaster and wipe before trying to loosen it. Even though it came off easily
this time, it was quite gunked up and greasy, and I think this, combined
with not having a 19 mm socket, was why the first time I did this it was was
hellacious. I really beat up one face of that bolt some 12 years ago.

Flush:
Per Tegger's suggestion and experience, I removed the engine block drain
bolt, closed the radiator petcock, and put a garden hose into the radiator
filler neck. Run until clear. Then open the radiator petcock and drain. I
did discover that the path of hose water flow is through the upper radiator
hose (from top of radiator to top of engine block), somewhat through the
block, and out the engine block's
coolant drain bolt hole. I speculate that the thermostat housing approach is
more effective. It's also more trouble, or it would have been for me this
time around.

About 1/8 teaspoon of sandy residue (both brown and white) came out of the
engine block with the old coolant, so I'm glad I took off the drain bolt and
"properly" drained the block.

I used (Permatex Ultra Grey) non-hardening sealant on the drain bolt
threads, per my manual's instructions. Permatex Ultra-Grey is advertised as
suitable for the water pump, so it made sense to me that it would be fine
for the drain bolt.

During the fill part of the procedure, I had to wait 36 minutes for the fan
to come on the first time; five minutes more to come on the second time. It
was 64 degrees F ambient temperature here.

I have been using the Orange Dexcool for the last 2.5 years in my Civic's
engine. It's supposed to be good for aluminum engines. Some others here say
they are using it in their Hondas, without problems. Still others say do not
experiment; it's not worth the risk; just by the pre-mixed Honda coolant
from your dealer.

In conclusion, I now have about as perfect a mix as possible of 50% Dex and
50% distilled water this time. Environmentally speaking, I didn't have all
that flushed, coolant-contaminated water to dispose of; just the roughly
1.35 gallons of old coolant.

Elle wrote:
> I paid about $18 last year for an OEM thermostat for my 1991 Civic. My
> recollection is folks here said the OEM was worth it. $18 seems cheap
> enough, compared to IIRC something like $10-$12 for non-OEM.

Right--I'm not worried about the cost, just whether it might be
important, now that I've got a brand-new aftermarket in there (not by my
choice), to replace the brand-new aftermarket with OEM. I too have noted
that some folks here prefer OEM thermostats.

> The good news, though,
> is that, if your 94 Civic is like my 91 Civic, it should be easy to give a
> pretty thorough flush. (It's more of a fill and drain as opposed to flush.)
> The reason it should be easy is that, by (1) opening the petcock on the
> radiator; (2) removing the engine block coolant drain bolt; and (3) emptying
> the reservoir, all coolant should come out of the system. I did careful
> measurements of what came out of (1) and (2) and they matched exactly what
> the manual stated should be the capacity for the system.

Thanks for this info and all the tips, Elle, exactly what I was looking
for. Alas, my socket sets don't include a 19 mm socket (if mine's the
same size)... Phooey. Well, I'll give a combo wrench a shot.

> I used (Permatex Ultra Grey) non-hardening sealant on the drain bolt
> threads, per my manual's instructions. Permatex Ultra-Grey is advertised as
> suitable for the water pump, so it made sense to me that it would be fine
> for the drain bolt.

Is this the stuff (one option, anyway) that's meant by "liquid gasket"?
I assume that using it would obviate the need for a washer.

> I have been using the Orange Dexcool for the last 2.5 years in my Civic's
> engine. It's supposed to be good for aluminum engines. Some others here say
> they are using it in their Hondas, without problems. Still others say do not
> experiment; it's not worth the risk; just by the pre-mixed Honda coolant
> from your dealer.

That's what I'll probably do, as I need to head down to the dealer to
pick up some manual tranny oil anyway, and don't want lots of extra
coolant lying around--no space. I had planned to use ordinary 10w-30 as
specified by the service manual till others here suggested that the
chemicals might not be right. Wonder what Honda uses... maybe ordinary
10w-30! ;-)

> Environmentally speaking, I didn't have all
> that flushed, coolant-contaminated water to dispose of; just the roughly
> 1.35 gallons of old coolant.

Yup, I'll probably do the same. Hopefully the local parts place will
take the old coolant. I've got a bunch of old brake fluid to dispose of
as well. Amazingly, my 1.6L engine holds only 1 gallon (plus the
reservoir, I presume). IIRC my old Pontiac held around 4!

"Abeness" > wrote
> Elle wrote:
> > I paid about $18 last year for an OEM thermostat for my 1991 Civic. My
> > recollection is folks here said the OEM was worth it. $18 seems cheap
> > enough, compared to IIRC something like $10-$12 for non-OEM.
>
> Right--I'm not worried about the cost, just whether it might be
> important, now that I've got a brand-new aftermarket in there (not by my
> choice), to replace the brand-new aftermarket with OEM. I too have noted
> that some folks here prefer OEM thermostats.

Just a thought: Maybe the thing won't fail catastrophically any sooner than
the OEM, but it might not regulate temperatures optimally. I think the
biggest concern is different temperature setpoints for opening and closing
the thermostat valve.

So other engine components, particularly those that regulate engine
operation, may not operate optimally.

I'm sure some of the regulars here can add to this.

> > The good news, though,
> > is that, if your 94 Civic is like my 91 Civic, it should be easy to give
a
> > pretty thorough flush. (It's more of a fill and drain as opposed to
flush.)
> > The reason it should be easy is that, by (1) opening the petcock on the
> > radiator; (2) removing the engine block coolant drain bolt; and (3)
emptying
> > the reservoir, all coolant should come out of the system. I did careful
> > measurements of what came out of (1) and (2) and they matched exactly
what
> > the manual stated should be the capacity for the system.
>
> Thanks for this info and all the tips, Elle, exactly what I was looking
> for. Alas, my socket sets don't include a 19 mm socket (if mine's the
> same size)... Phooey. Well, I'll give a combo wrench a shot.

Have another car standing by so you can run to Autozone and buy a 19 mm
socket (six-faced, not eight-faced, doh, pardon my earlier post-o) as
needed. :-)

Autozone IIRC will probably have the socket for under $6. I am pleased with
the sockets I've bought in the past from Autozone and found Autozone cheaper
than Pep Boys and Sears for sockets. Of course, one may get what one pays
for.

> > I used (Permatex Ultra Grey) non-hardening sealant on the drain bolt
> > threads, per my manual's instructions. Permatex Ultra-Grey is advertised
as
> > suitable for the water pump, so it made sense to me that it would be
fine
> > for the drain bolt.
>
> Is this the stuff (one option, anyway) that's meant by "liquid gasket"?

Yes. For example, the Permatex Ultra Grey's label includes the words "sensor
safe RTV silicone gasket maker."

But there are a few different grades of the stuff. The permatex.com site has
a good description of the different grades. Or just go to Autozone and read
what's on the packaging of the three or so grades it will likely have.

> I assume that using it would obviate the need for a washer.

I just checked Majestic's online parts site to compare a 94 Civic LX's drain
bolt with my 91 Civic LX's. It appears under "Cylinder Block-Oil Pan." The
91's and the 94's are the same.

They use a 28 mm washer. I've never replaced it and probably should.

My Civic Owner's Manual directs that "non-hardening sealant" be applied to
the drain bolt threads. (Chilton's says nothing about this. But I trust the
Owner's manual more for this.)

> > I have been using the Orange Dexcool for the last 2.5 years in my
Civic's
> > engine. It's supposed to be good for aluminum engines. Some others here
say
> > they are using it in their Hondas, without problems. Still others say do
not
> > experiment; it's not worth the risk; just by the pre-mixed Honda coolant
> > from your dealer.
>
> That's what I'll probably do, as I need to head down to the dealer to
> pick up some manual tranny oil anyway, and don't want lots of extra
> coolant lying around--no space.

True; you will only use about half of the gallon of DexCool.

> I had planned to use ordinary 10w-30 as
> specified by the service manual till others here suggested that the
> chemicals might not be right. Wonder what Honda uses... maybe ordinary
> 10w-30! ;-)

Well, I have been quite happy with Pennzoil 5W-30 for my car's engine oil,
for all its life. I mean, I notice nothing bad happening from it, at 168k
miles and 14 years. (5W-30 is the weight my owner's manual recommends for my
climate.)

> > Environmentally speaking, I didn't have all
> > that flushed, coolant-contaminated water to dispose of; just the roughly
> > 1.35 gallons of old coolant.
>
> Yup, I'll probably do the same. Hopefully the local parts place will
> take the old coolant. I've got a bunch of old brake fluid to dispose of
> as well.

For stuff like this, I've had a lot of luck with either (1) local government
run recycling centers; or (2) hazardous material recycling drives a couple
times a year; and (3) places like Autozone and independent garages taking
the stuff off my hands. Maybe check your yellow pages for "recycling." Or
call your city hall. They've always been eager to help with matters like
this.

Some folks say where they live, the law allows them to dump anti-freeze down
the drain sewer.

> Amazingly, my 1.6L engine holds only 1 gallon (plus the
> reservoir, I presume).

This is similar to the capacity of my 1.5 Liter engine. Your owner's manual,
if you have one, has the exact specs. Or there are some sites online that
will have it, like the free repair guides at www.autozone.com .

> IIRC my old Pontiac held around 4!

Honda rocks.

Elle wrote:
> Just a thought: Maybe the thing won't fail catastrophically any sooner than
> the OEM, but it might not regulate temperatures optimally.

That wouldn't kill me. I suspect it's close enough.

> Have another car standing by so you can run to Autozone and buy a 19 mm
> socket (six-faced, not eight-faced, doh, pardon my earlier post-o) as
> needed. :-)

Oh, no need for that, there's an autoparts place (Strauss) just a few
blocks away, and anyway I'd try to loosen the plug first--the coolant
doesn't pour out just from cracking it loose, if I got lucky. I do
prefer Craftsman, however, given that I've had el cheapo sockets come
apart on me when I need 'em most...

I use only 6-point sockets myself for best grippage. My combo wrenches
are 12-point, having been purchased before I realized the value of
6-point. It's easier to fit 12-point combo wrenches in tight spaces, anyway.

>>I had planned to use ordinary 10w-30 as
>>specified by the service manual till others here suggested that the
>>chemicals might not be right. Wonder what Honda uses... maybe ordinary
>>10w-30! ;-)
>
>
> Well, I have been quite happy with Pennzoil 5W-30 for my car's engine oil,
> for all its life. I mean, I notice nothing bad happening from it, at 168k
> miles and 14 years. (5W-30 is the weight my owner's manual recommends for my
> climate.)

Mine too; I was referring to tranny oil. All engine oils are created
equal, if they bear that grade stamp I forget the name of just now. For
the tranny, on the other hand, there was some discussion here about more
or less slippage adversely affecting the synchromesh gear system; hence
my caution.

> For stuff like this, I've had a lot of luck with either (1) local government
> run recycling centers; or (2) hazardous material recycling drives a couple
> times a year; and (3) places like Autozone and independent garages taking
> the stuff off my hands.

The local autoparts place will take motor oil; have to check on the
other stuff. I thought I might have seen something about coolant in the
sewer here, have to check on that too.

> This is similar to the capacity of my 1.5 Liter engine. Your owner's manual,
> if you have one, has the exact specs.

That number (1.00) is from the Helm manual.

> Honda rocks.

Yes indeed. My first one. I did enjoy the Pontiac, though, that monster
was nearly indestructable. I'm *really* sorry that my Honda bumpers are
just about useless and come apart at the slightest serious bump. On the
Pontiac, other bumpers were destroyed while merely a few chunks of rust
would fall out of mine (was rear-ended once on the highway).

Abeness wrote:
> Elle wrote:
>
>> Just a thought: Maybe the thing won't fail catastrophically any sooner
>> than
>> the OEM, but it might not regulate temperatures optimally.
>
>
> That wouldn't kill me. I suspect it's close enough.
>
>> Have another car standing by so you can run to Autozone and buy a 19 mm
>> socket (six-faced, not eight-faced, doh, pardon my earlier post-o) as
>> needed. :-)
>
>
> Oh, no need for that, there's an autoparts place (Strauss) just a few
> blocks away, and anyway I'd try to loosen the plug first--the coolant
> doesn't pour out just from cracking it loose, if I got lucky. I do
> prefer Craftsman, however, given that I've had el cheapo sockets come
> apart on me when I need 'em most...
>
> I use only 6-point sockets myself for best grippage. My combo wrenches
> are 12-point, having been purchased before I realized the value of
> 6-point. It's easier to fit 12-point combo wrenches in tight spaces,
> anyway.
>
>>> I had planned to use ordinary 10w-30 as
>>> specified by the service manual till others here suggested that the
>>> chemicals might not be right. Wonder what Honda uses... maybe ordinary
>>> 10w-30! ;-)
>>
>>
>>
>> Well, I have been quite happy with Pennzoil 5W-30 for my car's engine
>> oil,
>> for all its life. I mean, I notice nothing bad happening from it, at 168k
>> miles and 14 years. (5W-30 is the weight my owner's manual recommends
>> for my
>> climate.)
>
>
> Mine too; I was referring to tranny oil. All engine oils are created
> equal, if they bear that grade stamp

not true abe. sorry. massively different additive packages. different
base stocks. all the grade stamp does is spec /minima/.

> I forget the name of just now. For
> the tranny, on the other hand, there was some discussion here about more
> or less slippage adversely affecting the synchromesh gear system; hence
> my caution.
>
>> For stuff like this, I've had a lot of luck with either (1) local
>> government
>> run recycling centers; or (2) hazardous material recycling drives a
>> couple
>> times a year; and (3) places like Autozone and independent garages taking
>> the stuff off my hands.
>
>
> The local autoparts place will take motor oil; have to check on the
> other stuff. I thought I might have seen something about coolant in the
> sewer here, have to check on that too.
>
>> This is similar to the capacity of my 1.5 Liter engine. Your owner's
>> manual,
>> if you have one, has the exact specs.
>
>
> That number (1.00) is from the Helm manual.
>
>> Honda rocks.
>
>
> Yes indeed. My first one. I did enjoy the Pontiac, though, that monster
> was nearly indestructable. I'm *really* sorry that my Honda bumpers are
> just about useless and come apart at the slightest serious bump. On the
> Pontiac, other bumpers were destroyed while merely a few chunks of rust
> would fall out of mine (was rear-ended once on the highway).

jim beam wrote:
>> Mine too; I was referring to tranny oil. All engine oils are created
>> equal, if they bear that grade stamp
>
>
> not true abe. sorry. massively different additive packages. different
> base stocks. all the grade stamp does is spec /minima/.

Really? I've read differently on several occasions, though I can't
recall where now. Could you point me to a good discussion of differences
between grades (excluding synthetics)?

jim beam > wrote in
:

> Abeness wrote:

>> Mine too; I was referring to tranny oil. All engine oils are created
>> equal, if they bear that grade stamp
>
> not true abe. sorry. massively different additive packages.
> different base stocks. all the grade stamp does is spec /minima/.


There are several grade stamps. API, MB, ACEA, and ILSAC among them.

Not all oils carry all stamps, so there is considerable difference between
oils as far as compliance with engine makers' standards.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

"Abeness" > wrote
snip but comments noted
> >>I had planned to use ordinary 10w-30 as
> >>specified by the service manual till others here suggested that the
> >>chemicals might not be right. Wonder what Honda uses... maybe ordinary
> >>10w-30! ;-)
>
> Mine too; I was referring to tranny oil.

Oh okay.

> All engine oils are created
> equal, if they bear that grade stamp I forget the name of just now. For
> the tranny, on the other hand, there was some discussion here about more
> or less slippage adversely affecting the synchromesh gear system; hence
> my caution.

I'll have to look this up. I've been using Pennzoil 10W-30 (or 40 in the
climate where I now live) in my 91 Civic's tranny. The owner's manual
doesn't say Honda oil is necessary.

I thought it was newer Hondas that had stricter specs on the manual
transmission fluid.

TeGGeR® wrote:
> jim beam > wrote in
> :
>
>
>>Abeness wrote:
>
>
>>>Mine too; I was referring to tranny oil. All engine oils are created
>>>equal, if they bear that grade stamp
>>
>>not true abe. sorry. massively different additive packages.
>>different base stocks. all the grade stamp does is spec /minima/.
>
>
>
> There are several grade stamps. API, MB, ACEA, and ILSAC among them.
>
> Not all oils carry all stamps, so there is considerable difference between
> oils as far as compliance with engine makers' standards.

I'm talking about comparing apples with apples, however, not apples with
oranges. Is it not the case that oils bearing the same API grade stamp
(sans additives) provide at minimum the same engine protection
regardless of whether you buy the brand that's USD $2.50/qt. or the one
that's USD $1.00/qt.? Obviously, if you're buying an oil that bears
additional stamps that indicate adherence to higher standards or that
contains additives that increase protection, we'd be talking about a
different beast altogether.

Anyway, I suppose that is what Jim indicated: different additive
packages lead to different levels of protection. I'm not too worried
about it, however: Honda spec'd a minimum grade that you can't even buy
anymore the last I looked.