Honda Car Forum

I have a 92 Civic dx which is overheating. The radiator fan is not
coming on. I jumped it to the battery and it worked, so the motors
fine. I checked the relay and the fuses and all seem fine. I also
shorted the thermo switch plug and the fan came on, so the switch may
be bad, but it doesn't seem like any hot fluid is passing it. The
upper rad hose gets very hot, however the lower hose is cold. What
I've read is that if the upper hose is hot, then it means that the
thermostat is open, is that right? If so, why would the lower hose be
cold? It doesn't seem like any fuild is going through the lower hose,
but the thermostat is at the end of the lower hose. Does this make
sense to anyone? Am I misunderstanding this whole thing? Also I can't
get the damn bolts of the thermostat housing, they seem like they are
welded on, I tried a 13/ 32 socket and that cracked, so I went to
replace it and could find that size so I had to try a 10mm which seems
not as snug, but still the bolts don't budge. Any suggestions?

ohnickleman@yahoo.com wrote:
> I have a 92 Civic dx which is overheating. The radiator fan is not
> coming on. I jumped it to the battery and it worked, so the motors
> fine. I checked the relay and the fuses and all seem fine. I also
> shorted the thermo switch plug and the fan came on, so the switch may
> be bad, but it doesn't seem like any hot fluid is passing it. The
> upper rad hose gets very hot, however the lower hose is cold. What
> I've read is that if the upper hose is hot, then it means that the
> thermostat is open, is that right?

don't think so with the honda. the thermostat is on the "cold" side of
the coolant loop, so i think it works by having some of the hot bypass
the activation end of the thermostat. once the t-stat opens, that'll
regulate the resultant temperature mix passing through the pump and back
into the block. to answer your question however, it sounds like you
need to test the switch [rear side of the block and hard to get at iirc].

> If so, why would the lower hose be
> cold? It doesn't seem like any fuild is going through the lower hose,
> but the thermostat is at the end of the lower hose. Does this make
> sense to anyone? Am I misunderstanding this whole thing? Also I can't
> get the damn bolts of the thermostat housing, they seem like they are
> welded on, I tried a 13/ 32 socket and that cracked,

every bolt on a honda is metric. use quality tools to avoid breakage
and subsequent injury.

> so I went to
> replace it and could find that size so I had to try a 10mm which seems
> not as snug, but still the bolts don't budge. Any suggestions?
>

replacing the t-stat [with oem] is a good thing [don't forget to replace
the rubber gasket too], but i'm not sure it's necessary in this
instance. even if the t-stat's failed closed, the fan should still come
on because the switch is in the block, not the radiator. check all the
leads for good connection, in addition to fuses and relays. again.

Jim thanks for the quick response.

> to answer your question however, it sounds like you
> need to test the switch [rear side of the block and hard to get at iirc].

Just to clarify,when you say "test the switch", which switch are you
refering to? the coolant temp switch?

also shouldn't the bottom hose aleast be warm? especially sense the fan
isn't working. it really seems like there is no fuild going through
that bottom hose. Do you have any thoughts on why that might be?

Thanks again

ohnickleman@yahoo.com wrote in
news:1140480146.912201.212010@f14g2000cwb.googlegr oups.com:

> I have a 92 Civic dx which is overheating. The radiator fan is not
> coming on. I jumped it to the battery and it worked, so the motors
> fine. I checked the relay and the fuses and all seem fine. I also
> shorted the thermo switch plug and the fan came on, so the switch may
> be bad, but it doesn't seem like any hot fluid is passing it. The
> upper rad hose gets very hot, however the lower hose is cold. What
> I've read is that if the upper hose is hot, then it means that the
> thermostat is open, is that right? If so, why would the lower hose be
> cold? It doesn't seem like any fuild is going through the lower hose,
> but the thermostat is at the end of the lower hose. Does this make
> sense to anyone? Am I misunderstanding this whole thing? Also I can't
> get the damn bolts of the thermostat housing, they seem like they are
> welded on, I tried a 13/ 32 socket and that cracked, so I went to
> replace it and could find that size so I had to try a 10mm which seems
> not as snug, but still the bolts don't budge. Any suggestions?
>
>

My Haynes manual for 94-00 Integra says if the upper hose is hot,coolant is
flowing and the thermostat is open,so your ECT (engine coolant temp)switch
is probably bad. You can check it with an ohmmeter(connector removed),it
should measure open with the motor cold,and shorted when the motor reaches
the proper temp,probably 180 degF(Integra GSR is 195 degF).You should check
the manual for your auto,it will give you the correct temp for your motor.

Torque settings for the TS housing bolts for my motor is 104 ft-lbs.
You may need a breaker bar and/or penetrating oil (*not* WD-40)to get the
bolts loose,the bolt is steel in a aluminum block,and corrosion may have
frozen the bolt threads. A 6-point socket(METRIC!) may be advisable,too.

Access was tight on my Integra,too.

I've found that cheap sockets are looser than quality ones.

--
Jim Yanik
jyanik
at
kua.net

ohnickleman@yahoo.com wrote:
> Jim thanks for the quick response.
>
>
>>to answer your question however, it sounds like you
>>need to test the switch [rear side of the block and hard to get at iirc].
>
>
> Just to clarify,when you say "test the switch", which switch are you
> refering to? the coolant temp switch?

yes, the switch on the block that turns the fan on & off. /not/ the
temp sensors that the ecu or the instrument temp gauge uses.

>
> also shouldn't the bottom hose aleast be warm? especially sense the fan
> isn't working. it really seems like there is no fuild going through
> that bottom hose. Do you have any thoughts on why that might be?
>
> Thanks again
>
it's winter - the bottom hose won't get very hot unless the engine's
working hard and will quickly cool again. and if your radiator's doing
its job. nevertheless, make sure the system has sufficient coolant.
look inside the radiator. if there's an air leak, the expansion bottle
doesn't give a reading on coolant level.

Jim Yanik wrote:
> ohnickleman@yahoo.com wrote in
> news:1140480146.912201.212010@f14g2000cwb.googlegr oups.com:
>
>
>>I have a 92 Civic dx which is overheating. The radiator fan is not
>>coming on. I jumped it to the battery and it worked, so the motors
>>fine. I checked the relay and the fuses and all seem fine. I also
>>shorted the thermo switch plug and the fan came on, so the switch may
>>be bad, but it doesn't seem like any hot fluid is passing it. The
>>upper rad hose gets very hot, however the lower hose is cold. What
>>I've read is that if the upper hose is hot, then it means that the
>>thermostat is open, is that right? If so, why would the lower hose be
>>cold? It doesn't seem like any fuild is going through the lower hose,
>>but the thermostat is at the end of the lower hose. Does this make
>>sense to anyone? Am I misunderstanding this whole thing? Also I can't
>>get the damn bolts of the thermostat housing, they seem like they are
>>welded on, I tried a 13/ 32 socket and that cracked, so I went to
>>replace it and could find that size so I had to try a 10mm which seems
>>not as snug, but still the bolts don't budge. Any suggestions?
>>
>>
>
>
> My Haynes manual for 94-00 Integra says if the upper hose is hot,coolant is
> flowing

haynes manual just regurgitates standard text. throw the wretched thing
away. the honda t-stat is on the cool side of the circuit - that should
be apparent just by looking at which hose it's connected to!

> and the thermostat is open,so your ECT (engine coolant temp)switch
> is probably bad. You can check it with an ohmmeter(connector removed),it
> should measure open with the motor cold,and shorted when the motor reaches
> the proper temp,probably 180 degF(Integra GSR is 195 degF).You should check
> the manual for your auto,it will give you the correct temp for your motor.
>
> Torque settings for the TS housing bolts for my motor is 104 ft-lbs.
> You may need a breaker bar and/or penetrating oil (*not* WD-40)to get the
> bolts loose,the bolt is steel in a aluminum block,and corrosion may have
> frozen the bolt threads. A 6-point socket(METRIC!) may be advisable,too.
>
> Access was tight on my Integra,too.
>
> I've found that cheap sockets are looser than quality ones.
>

jim beam <nospam@example.net> wrote in news:m46dnYN2YoNJwWfenZ2dnUVZ_v-
dnZ2d@speakeasy.net:

> ohnickleman@yahoo.com wrote:
>> I have a 92 Civic dx which is overheating. The radiator fan is not
>> coming on. I jumped it to the battery and it worked, so the motors
>> fine. I checked the relay and the fuses and all seem fine. I also
>> shorted the thermo switch plug and the fan came on, so the switch may
>> be bad, but it doesn't seem like any hot fluid is passing it. The
>> upper rad hose gets very hot, however the lower hose is cold. What
>> I've read is that if the upper hose is hot, then it means that the
>> thermostat is open, is that right?
>
> don't think so with the honda. the thermostat is on the "cold" side of
> the coolant loop,

That would be utterly stupid.
The TS keeps the coolant *circulating in the BLOCK* until the motor reaches
temp,then the TS opens to allow coolant to flow thru the radiator.
Or do you think the water pump stops while the TS is closed?




--
Jim Yanik
jyanik
at
kua.net

jim beam <nospam@example.net> wrote in
news:KJadnQt7lerr7GfeRVn-iA@speakeasy.net:

> Jim Yanik wrote:
>> ohnickleman@yahoo.com wrote in
>> news:1140480146.912201.212010@f14g2000cwb.googlegr oups.com:
>>
>>
>>>I have a 92 Civic dx which is overheating. The radiator fan is not
>>>coming on. I jumped it to the battery and it worked, so the motors
>>>fine. I checked the relay and the fuses and all seem fine. I also
>>>shorted the thermo switch plug and the fan came on, so the switch may
>>>be bad, but it doesn't seem like any hot fluid is passing it. The
>>>upper rad hose gets very hot, however the lower hose is cold. What
>>>I've read is that if the upper hose is hot, then it means that the
>>>thermostat is open, is that right? If so, why would the lower hose
>>>be cold? It doesn't seem like any fuild is going through the lower
>>>hose, but the thermostat is at the end of the lower hose. Does this
>>>make sense to anyone? Am I misunderstanding this whole thing? Also
>>>I can't get the damn bolts of the thermostat housing, they seem like
>>>they are welded on, I tried a 13/ 32 socket and that cracked, so I
>>>went to replace it and could find that size so I had to try a 10mm
>>>which seems not as snug, but still the bolts don't budge. Any
>>>suggestions?
>>>
>>>
>>
>>
>> My Haynes manual for 94-00 Integra says if the upper hose is
>> hot,coolant is flowing
>
> haynes manual just regurgitates standard text. throw the wretched
> thing away. the honda t-stat is on the cool side of the circuit -
> that should be apparent just by looking at which hose it's connected
> to!

That would be utterly stupid.
The TS keeps the coolant circulating in the BLOCK until the motor reaches
temp,then the TS opens to allow coolant to flow thru the radiator.

>
>> and the thermostat is open,so your ECT (engine coolant temp)switch
>> is probably bad. You can check it with an ohmmeter(connector
>> removed),it should measure open with the motor cold,and shorted when
>> the motor reaches the proper temp,probably 180 degF(Integra GSR is
>> 195 degF).You should check the manual for your auto,it will give you
>> the correct temp for your motor.

I may be wrong here;the ECT is a thermistor and measured by the ECU,the
manual has an ohms chart for it.(for my 94 Integra and 94 Civics,so I can't
speak for earlier Hondas.)

>>
>> Torque settings for the TS housing bolts for my motor is 104 ft-lbs.
>> You may need a breaker bar and/or penetrating oil (*not* WD-40)to get
>> the bolts loose,the bolt is steel in a aluminum block,and corrosion
>> may have frozen the bolt threads. A 6-point socket(METRIC!) may be
>> advisable,too.
>>
>> Access was tight on my Integra,too.
>>
>> I've found that cheap sockets are looser than quality ones.
>>



--
Jim Yanik
jyanik
at
kua.net

Jim Yanik wrote:
> jim beam <nospam@example.net> wrote in news:m46dnYN2YoNJwWfenZ2dnUVZ_v-
> dnZ2d@speakeasy.net:
>
>
>>ohnickleman@yahoo.com wrote:
>>
>>>I have a 92 Civic dx which is overheating. The radiator fan is not
>>>coming on. I jumped it to the battery and it worked, so the motors
>>>fine. I checked the relay and the fuses and all seem fine. I also
>>>shorted the thermo switch plug and the fan came on, so the switch may
>>>be bad, but it doesn't seem like any hot fluid is passing it. The
>>>upper rad hose gets very hot, however the lower hose is cold. What
>>>I've read is that if the upper hose is hot, then it means that the
>>>thermostat is open, is that right?
>>
>>don't think so with the honda. the thermostat is on the "cold" side of
>>the coolant loop,
>
>
> That would be utterly stupid.

not if you take a moment to understand what's going on.

> The TS keeps the coolant *circulating in the BLOCK*

it can't circulate unless there is a channel it can flow through. put a
valve on a garden hose - the water will NOT flow /regardless/ of which
end of the hose it's on if the valve's not open.

> until the motor reaches
> temp,then the TS opens to allow coolant to flow thru the radiator.
> Or do you think the water pump stops while the TS is closed?

of course not! it's an impeller - there's no hydrostatic lock so it
can turn regardless.

besides, there /is/ a flow channel. go look under the hood at at your
civic's coolant pipes and describe what you see. then let's talk it
through together.

>
>
>
>

Jim Yanik wrote:
> jim beam <nospam@example.net> wrote in
> news:KJadnQt7lerr7GfeRVn-iA@speakeasy.net:
>
>
>>Jim Yanik wrote:
>>
>>>ohnickleman@yahoo.com wrote in
>>>news:1140480146.912201.212010@f14g2000cwb.googl egroups.com:
>>>
>>>
>>>
>>>>I have a 92 Civic dx which is overheating. The radiator fan is not
>>>>coming on. I jumped it to the battery and it worked, so the motors
>>>>fine. I checked the relay and the fuses and all seem fine. I also
>>>>shorted the thermo switch plug and the fan came on, so the switch may
>>>>be bad, but it doesn't seem like any hot fluid is passing it. The
>>>>upper rad hose gets very hot, however the lower hose is cold. What
>>>>I've read is that if the upper hose is hot, then it means that the
>>>>thermostat is open, is that right? If so, why would the lower hose
>>>>be cold? It doesn't seem like any fuild is going through the lower
>>>>hose, but the thermostat is at the end of the lower hose. Does this
>>>>make sense to anyone? Am I misunderstanding this whole thing? Also
>>>>I can't get the damn bolts of the thermostat housing, they seem like
>>>>they are welded on, I tried a 13/ 32 socket and that cracked, so I
>>>>went to replace it and could find that size so I had to try a 10mm
>>>>which seems not as snug, but still the bolts don't budge. Any
>>>>suggestions?
>>>>
>>>>
>>>
>>>
>>>My Haynes manual for 94-00 Integra says if the upper hose is
>>>hot,coolant is flowing
>>
>>haynes manual just regurgitates standard text. throw the wretched
>>thing away. the honda t-stat is on the cool side of the circuit -
>>that should be apparent just by looking at which hose it's connected
>>to!
>
>
> That would be utterly stupid.
> The TS keeps the coolant circulating in the BLOCK until the motor reaches
> temp,then the TS opens to allow coolant to flow thru the radiator.
>
>
>>>and the thermostat is open,so your ECT (engine coolant temp)switch
>>>is probably bad. You can check it with an ohmmeter(connector
>>>removed),it should measure open with the motor cold,and shorted when
>>>the motor reaches the proper temp,probably 180 degF(Integra GSR is
>>>195 degF).You should check the manual for your auto,it will give you
>>>the correct temp for your motor.
>
>
> I may be wrong here;the ECT is a thermistor and measured by the ECU,the
> manual has an ohms chart for it.(for my 94 Integra and 94 Civics,so I can't
> speak for earlier Hondas.)

there are three thermoelectronic devices used on this motor:

1. the thermistor that feeds back to the ecu.
2. the thermistor that controls the temperature reading on the
instrument panel.
3. the thermoswitch that controls the fan.

#3 is the ect.

>
>
>>>Torque settings for the TS housing bolts for my motor is 104 ft-lbs.
>>>You may need a breaker bar and/or penetrating oil (*not* WD-40)to get
>>>the bolts loose,the bolt is steel in a aluminum block,and corrosion
>>>may have frozen the bolt threads. A 6-point socket(METRIC!) may be
>>>advisable,too.
>>>
>>>Access was tight on my Integra,too.
>>>
>>>I've found that cheap sockets are looser than quality ones.
>>>
>
>
>
>