98 Accord cooling fans. What operates and when? Erratic overheating episodes.

My driver side fan runs with the A/C always...also runs after shut-off
for the requisite 5-10 minutes. Never seen the right-side fan
run...esp now that I'm looking for it. I'm having intermittent near-
overheating episodes. But once the guage starts to climb and I dump
the A/C and goto full HEATER on HI...that guage drops like a hot rock
back to normal! And I mean in a matter of 10-15 seconds! Any engine
overheating due to damage/lubrication and block/head heat will not
move the guage from Critical to Normal just by introducing the heater
core circulation. So it has to be more local, right? And no, I
haven't invaded the coolant circuit for a year or so...and it's full.
It has been bled-out. Sensor? T-stat? That other fan? Thanks
dudes!
-
-
See, isn't this better than BS posters from China posting spam rubbish
every day? HAHA!!! A 'REAL tech question!

Meatman > wrote in news:003e0486-f13b-42f9-be12-
:

> My driver side fan runs with the A/C always...also runs after shut-off
> for the requisite 5-10 minutes. Never seen the right-side fan
> run...esp now that I'm looking for it. I'm having intermittent near-
> overheating episodes. But once the guage starts to climb and I dump
> the A/C and goto full HEATER on HI...that guage drops like a hot rock
> back to normal! And I mean in a matter of 10-15 seconds! Any engine
> overheating due to damage/lubrication and block/head heat will not
> move the guage from Critical to Normal just by introducing the heater
> core circulation. So it has to be more local, right? And no, I
> haven't invaded the coolant circuit for a year or so...and it's full.
> It has been bled-out. Sensor? T-stat? That other fan? Thanks
> dudes!



The rad fan (the right one) has two temperature and/or timer switches. One
of them is bad. I /think/ there are two of them, and not just one.

You said earlier you have the Helms manual for the car. Go to the A/C
section and you should find the switches' locations and how to test them.


--
Tegger

On 08/24/2011 01:22 AM, Meatman wrote:
> My driver side fan runs with the A/C always...also runs after shut-off
> for the requisite 5-10 minutes. Never seen the right-side fan
> run...esp now that I'm looking for it. I'm having intermittent near-
> overheating episodes. But once the guage starts to climb and I dump
> the A/C and goto full HEATER on HI...that guage drops like a hot rock
> back to normal! And I mean in a matter of 10-15 seconds! Any engine
> overheating due to damage/lubrication and block/head heat will not
> move the guage from Critical to Normal just by introducing the heater
> core circulation. So it has to be more local, right? And no, I
> haven't invaded the coolant circuit for a year or so...and it's full.
> It has been bled-out. Sensor? T-stat? That other fan? Thanks
> dudes!
> -
> -
> See, isn't this better than BS posters from China posting spam rubbish
> every day? HAHA!!! A 'REAL tech question!

what tegger says on the thermo-switches.

but also consider the possibility of the head gasket going as being the
root of the overheating. [bubbles/foam in the coolant lower its density
and significantly reduce cooling capacity.]

i say this because your other fuel smell when reversing comment could be
that aromatic odor from when a little coolant has leaked into a cylinder
head overnight. and because head gasket is a common honda failure that
often goes undetected for a considerable period. the open deck honda
block means you just get gas in the coolant, you don't get much coolant
loss [until it's getting really bad] and you don't get oil in the
coolant or vice versa.

with the motor at full temperature and running, look in the coolant
expansion bottle. if you observe any bubbling, it's definitely head
gasket. you can confirm this with a chemical test if you want too.

if it ends up being gasket, i recommend a few of important things.

1. don't use abrasives in clean-up. even if you hose everything off
afterwards, it's next to impossible to remove tiny abrasive particles
from metal surfaces, and those inevitably end up circulating the system
causing significant premature wear.

2. try not to skim the head unless it's actually warped. and warping on
honda heads is rare. use gasket remover [chemical] and a razor blade
[thin, flexible] scraper at a shallow angle to avoid damaging the head
surface for clean-up. i've never yet seem a shop skim a head to the
same finish as oem. the small grooves they leave from the milling head
are small leakage channels - the head will be fine for a short while,
but will quickly start to leak again. avoid avoid avoid.

3. for the new gasket, i recommend "mls" [multi layer steel]. it's the
only solution that can begin to address the root cause of gasket failure
- the fact that there is small elastic distortion at the block/head
interface, and a gap tends to open up at the point furthest from the
head bolts. a [properly designed and made] "variable thickness" mls
gasket is the only solution that can address this since milling a head
or a block to be anything other than flat is impractical. [it works
like the bowed bed of a big rig trailer that ends up flat when loaded.]

4. when tightening head bolts, torque in the honda steps and sequence,
but go around at the final torque several times, paying particular
attention to the center two bolts. also use a bending beam wrench, not
a clicker. honda head bolts tend to be sticky, even when cleaned and
lubed [it's the aluminum/steel thing] and clicker wrenches sometimes
release on stickiness leaving a low torque. they also tend to creep
around, so again, torque and hold with the bending beam and follow it
around.

hth.


--
nomina rutrum rutrum

Not head-gasket. .....I retraced my/and brother's test and confirmed
this in my case, at least: Ran car well up to temp (several hours).
Know that BOTH fans should run when A/C is on. They
weren't...HOWEVER...with only condenser fan running I took a weak
stick/twig and spun the fan blade manually (rad fan on pass side)...it
would start/stop after a few rev's or would would run continuous for
maybe a minute, always ridiculously slow and just barely getting
along. 265k on this fan motor, mind you. Further, I put probes in
connector at fan motor and proper voltage was continuous for 10
mins....but no fan spin unless I 'helped' it as above. Therefore,
it's the motor IMHO given the continuous power at connector and fact
that it runs, then falters after external help.

Meatman > wrote in news:3879eca7-519c-4e3d-9ac1-
:

>
> Not head-gasket. .....I retraced my/and brother's test and confirmed
> this in my case, at least: Ran car well up to temp (several hours).
> Know that BOTH fans should run when A/C is on. They
> weren't...HOWEVER...with only condenser fan running I took a weak
> stick/twig and spun the fan blade manually (rad fan on pass side)...it
> would start/stop after a few rev's or would would run continuous for
> maybe a minute, always ridiculously slow and just barely getting
> along. 265k on this fan motor, mind you. Further, I put probes in
> connector at fan motor and proper voltage was continuous for 10
> mins....but no fan spin unless I 'helped' it as above. Therefore,
> it's the motor IMHO given the continuous power at connector and fact
> that it runs, then falters after external help.
>



I agree with your findings.

My suspicions arose from the fact that it's far more common for the timers
to fail than for the motor to fail. New motors are close to $400. Honda
builds them VERY well.

--
Tegger

On 08/30/2011 12:38 AM, Meatman wrote:
>
> Not head-gasket. .....I retraced my/and brother's test and confirmed
> this in my case, at least:

ok good. i bleat about head gaskets because it is often undiagnosed
until it gets really bad, and causes other expensive problems like dead
catalytic converters.


> Ran car well up to temp (several hours).
> Know that BOTH fans should run when A/C is on. They
> weren't...HOWEVER...with only condenser fan running I took a weak
> stick/twig and spun the fan blade manually (rad fan on pass side)...it
> would start/stop after a few rev's or would would run continuous for
> maybe a minute, always ridiculously slow and just barely getting
> along. 265k on this fan motor, mind you. Further, I put probes in
> connector at fan motor and proper voltage was continuous for 10
> mins....but no fan spin unless I 'helped' it as above. Therefore,
> it's the motor IMHO given the continuous power at connector and fact
> that it runs, then falters after external help.

good diagnostic. while it's possible to recondition the bearings in
motors like this, it's generally a pita - just replace.

when fitting the replacement motor, try to get some sealant or grease
into the mounting to prevent water ingress, the most likely cause. and
make sure the water drain isn't obstructed. i would also change the
thermoswitch - if it's been switching against a stationary motor, it
will have been loaded much more than normal and is likely to be
overheated and not much longer for this world.


--
nomina rutrum rutrum

On 08/30/2011 04:14 AM, Tegger wrote:
> > wrote in news:3879eca7-519c-4e3d-9ac1-
> :
>
>>
>> Not head-gasket. .....I retraced my/and brother's test and confirmed
>> this in my case, at least: Ran car well up to temp (several hours).
>> Know that BOTH fans should run when A/C is on. They
>> weren't...HOWEVER...with only condenser fan running I took a weak
>> stick/twig and spun the fan blade manually (rad fan on pass side)...it
>> would start/stop after a few rev's or would would run continuous for
>> maybe a minute, always ridiculously slow and just barely getting
>> along. 265k on this fan motor, mind you. Further, I put probes in
>> connector at fan motor and proper voltage was continuous for 10
>> mins....but no fan spin unless I 'helped' it as above. Therefore,
>> it's the motor IMHO given the continuous power at connector and fact
>> that it runs, then falters after external help.
>>
>
>
>
> I agree with your findings.
>
> My suspicions arose from the fact that it's far more common for the timers
> to fail than for the motor to fail. New motors are close to $400. Honda
> builds them VERY well.
>

honda doesn't build them, they buy them in. and they charge about 10x
what you could buy them for if you were sourcing them from their
original supplier. if you were buying retail. which of course they
are not.


--
nomina rutrum rutrum

Tigger & Beamer:
-
Thanks kindly, as always. Veeery fair point on the thermo-switches
switching against a hung motor...But actually, methinks, that
'switching is switching' in general...it does what it does and doesn't
care if the motor runs or not...and only adds to the 'ultimate fatigue
failure' level/count. In and of itself, switching against a hung
motor is no more fatiguing than anything else. But at 265k on this
motor & switches, normal expected lifespan AND extra switching due to
overheat due to flagging fan motor, become part and parcel. At any
other point (100k) in the car's life I would be waaay less wary of the
extra switching caused by the failing motor/overheat. So, I'll keep
watch, indeed.
-
And as for the head-gask: I know yous guys work a lot, read a lot,
suffer through our gibberish, and try to respond accurately/promptly
given all of that. But, dadgummit, Beamer, you gave me tons of good
useful stuff in the h-gasket response, but, I said that there was no
overnight/cold-start odor. Not a slap, B. Just sorry you went that
far in the response....cause you wrote A TON!
-
Thanks dudes. K.

On 08/31/2011 12:56 AM, Meatman wrote:
> Tigger& Beamer:
> -
> Thanks kindly, as always. Veeery fair point on the thermo-switches
> switching against a hung motor...But actually, methinks, that
> 'switching is switching' in general...it does what it does and doesn't
> care if the motor runs or not...and only adds to the 'ultimate fatigue
> failure' level/count. In and of itself, switching against a hung
> motor is no more fatiguing than anything else. But at 265k on this
> motor& switches, normal expected lifespan AND extra switching due to
> overheat due to flagging fan motor, become part and parcel. At any
> other point (100k) in the car's life I would be waaay less wary of the
> extra switching caused by the failing motor/overheat. So, I'll keep
> watch, indeed.

switching is not just switching, unfortunately. the load is highly
relevant. if it's a reactive load, which the coils in a motor are, you
can get extensive arcing on the switch contacts, and thus you need a
much bigger switch capacity than for a non-reactive load like an
incandescent light bulb, even of the same nominal power draw. now, if
you're switching a motor that is actually free to spin, your power draw
drops significantly once running and switch-off reaction, the one where
you get the arcing, is minimized. if the motor is not spinning, not
only is the draw greater, but you've got no spinning commutator
interrupting the arcing, so the switch can be over-loaded.


> -
> And as for the head-gask: I know yous guys work a lot, read a lot,
> suffer through our gibberish, and try to respond accurately/promptly
> given all of that. But, dadgummit, Beamer, you gave me tons of good
> useful stuff in the h-gasket response, but, I said that there was no
> overnight/cold-start odor. Not a slap, B. Just sorry you went that
> far in the response....cause you wrote A TON!

well, it's good you're not in that position. i wrote all that out not
just for you, but because it's a common problem and others may benefit.


> -
> Thanks dudes. K.


--
nomina rutrum rutrum

Hmm..methinks I see. (?) I supposed I imagined, not intentionally,
the switch as external to the circuit/load/draw once it 'di it's
job'. When, DUH, it IS obviously in the loop. So as you said, the
draw of a hung motor just 'trying' to run taxes everything in the
circuit in one way or another and to varying degrees depending...
-
Thx!