95 Accord runs hot on freeway

"pinkfloyd" <none.DeleteThis@000.com> wrote in message
news:965002_e0d918b8d5f7b207ad5d229ebae4e321@autoboardz.com...
>I have a 95 Accord which starts to run hot after about 15 to 20
> minutes of driving on the freeway. It runs at normal temperature on
> surface streets. I know for sure that the fans are working properly.
>
> I've taken it to 2 mechanics and one says it's the main fan motor and
> possibly the thermostat. The other mechanic thinks the radiator needs
> to be replaced due to a clog, and if not that, then it is most likely
> the head gasket leaking. I'm really confused here. Any help would be
> greatly appreciated.
>
>
Jim beam's advice is solid. I'd add that I suspect the radiator more than
the thermostat because the heat builds up, but that assumes it isn't the
head gasket.

My own head gasket test is more sensitive but has the disadvantage that the
leak may not be as obvious when cold. I test with a cold engine by removing
the radiator cap and starting the engine. I pinch off the overflow tube and
put the palm of my hand over the radiator opening for a few seconds.
Steadily rising pressure or (worse) pulsations indicate a head gasket
failure.

If either jim's test or mine indicate trouble, shops can do chemical tests
for hydrocarbons in the coolant to confirm the problem.

Mike
 >> Stay informed about: 95 Accord runs hot on freeway 

pinkfloyd <none DeleteThis @000.com> wrote in news:965002
_e0d918b8d5f7b207ad5d229ebae4e321 DeleteThis @autoboardz.com:

> I have a 95 Accord which starts to run hot after about 15 to 20
> minutes of driving on the freeway. It runs at normal temperature on
> surface streets. I know for sure that the fans are working properly.
>
> I’ve taken it to 2 mechanics and one says it’s the main fan motor and
> possibly the thermostat. The other mechanic thinks the radiator needs
> to be replaced due to a clog, and if not that, then it is most likely
> the head gasket leaking. I’m really confused here. Any help would be
> greatly appreciated.
>



If it runs fine on city street but not on the highway, it's most likely a
clogged rad.

A test: Next time it starts to overheat, turn the car's interior heater on
full-hot, along with the fan on full-blast. Does this make the needle go
down? If so, the rad isn't cooling properly.

One thing to check is the fins at the bottom of the rad. If they corrode
and turn to dust, the rad will be unable to shed heat efficiently.

--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: 95 Accord runs hot on freeway 

Thank you for the great and very helpful replies. I am going to try the things recommended here. Also, the mechanic that thinks it's the radiator, says that since the radiator is plastic, it needs to be replaced. It cannot be flushed. Is this correct?

Since I have never had to do so, what would be the best place to start to find a shop that can do the chemical test for hydrocarbons in the coolant?
 >> Stay informed about: 95 Accord runs hot on freeway 

Today I checked every recommendation posted.

First I tried the cold method to check for possibility of bad head gasket. I pinched the reservoir hose, and placed my palm on the radiator opening. I did not feel any pulsating.

Second, after a long drive on the freeway, when I stopped, I checked the reservoir, and there were no bubbles.

Third, while driving on the freeway back home, when the car started to heat up, I turned on the heater full blast, and the temp cooled down right away.
 >> Stay informed about: 95 Accord runs hot on freeway 

pinkfloyd <none.RemoveThis@000.com> wrote in news:965321
_bbd9486094e485fede355cb837e57234.RemoveThis@0000.com:

> Today I checked every recommendation posted.
>
> First I tried the cold method to check for possibility of bad head
> gasket. I pinched the reservoir hose, and placed my palm on the
> radiator opening. I did not feel any pulsating.
>
> Second, after a long drive on the freeway, when I stopped, I checked
> the reservoir, and there were no bubbles.
>
> Third, while driving on the freeway back home, when the car started to
> heat up, I turned on the heater full blast, and the temp cooled down
> right away.



Then your rad is internally blocked (or the fins have fallen off).


--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: 95 Accord runs hot on freeway 

Tegger <tegger.DeleteThis@tegger.c0m> wrote in
news:Xns98BBBE00C4F5Ftegger@207.14.116.130:

> pinkfloyd <none.DeleteThis@000.com> wrote in news:965321
> _bbd9486094e485fede355cb837e57234.DeleteThis@0000.com:
>
>> Today I checked every recommendation posted.
>>
>> First I tried the cold method to check for possibility of bad head
>> gasket. I pinched the reservoir hose, and placed my palm on the
>> radiator opening. I did not feel any pulsating.
>>
>> Second, after a long drive on the freeway, when I stopped, I checked
>> the reservoir, and there were no bubbles.
>>
>> Third, while driving on the freeway back home, when the car started to
>> heat up, I turned on the heater full blast, and the temp cooled down
>> right away.
>
>
>
> Then your rad is internally blocked (or the fins have fallen off).
>
>

First put a new Honda thermostat in it.Not some aftermarket TS,a real Honda
TS.

--
Jim Yanik
jyanik
at
kua.net
 >> Stay informed about: 95 Accord runs hot on freeway 

Jim Yanik <jyanik DeleteThis @abuse.gov> wrote in
news:Xns98BBC9816FB52jyanikkuanet@64.209.0.86:

> Tegger <tegger DeleteThis @tegger.c0m> wrote in
> news:Xns98BBBE00C4F5Ftegger@207.14.116.130:
>
>> pinkfloyd <none DeleteThis @000.com> wrote in news:965321
>> _bbd9486094e485fede355cb837e57234 DeleteThis @0000.com:
>>
>>> Today I checked every recommendation posted.
>>>
>>> First I tried the cold method to check for possibility of bad head
>>> gasket. I pinched the reservoir hose, and placed my palm on the
>>> radiator opening. I did not feel any pulsating.
>>>
>>> Second, after a long drive on the freeway, when I stopped, I checked
>>> the reservoir, and there were no bubbles.
>>>
>>> Third, while driving on the freeway back home, when the car started
>>> to heat up, I turned on the heater full blast, and the temp cooled
>>> down right away.
>>
>>
>>
>> Then your rad is internally blocked (or the fins have fallen off).
>>
>>
>
> First put a new Honda thermostat in it.Not some aftermarket TS,a real
> Honda TS.
>



It's not his thermostat. I'm sure of that.

--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: 95 Accord runs hot on freeway 

"Tegger" <tegger.RemoveThis@tegger.c0m> wrote in message
news:Xns98BBCB1FB5862tegger@207.14.116.130...
> Jim Yanik <jyanik.RemoveThis@abuse.gov> wrote in
> news:Xns98BBC9816FB52jyanikkuanet@64.209.0.86:
>
> > Tegger <tegger.RemoveThis@tegger.c0m> wrote in
> > news:Xns98BBBE00C4F5Ftegger@207.14.116.130:
> >
> >> pinkfloyd <none.RemoveThis@000.com> wrote in news:965321
> >> _bbd9486094e485fede355cb837e57234.RemoveThis@0000.com:
> >>
> >>> Today I checked every recommendation posted.
> >>>
> >>> First I tried the cold method to check for possibility of bad head
> >>> gasket. I pinched the reservoir hose, and placed my palm on the
> >>> radiator opening. I did not feel any pulsating.
> >>>
> >>> Second, after a long drive on the freeway, when I stopped, I checked
> >>> the reservoir, and there were no bubbles.
> >>>
> >>> Third, while driving on the freeway back home, when the car started
> >>> to heat up, I turned on the heater full blast, and the temp cooled
> >>> down right away.
> >>
> >>
> >>
> >> Then your rad is internally blocked (or the fins have fallen off).
> >>
> >>
> >
> > First put a new Honda thermostat in it.Not some aftermarket TS,a real
> > Honda TS.
> >
>
>
>
> It's not his thermostat. I'm sure of that.
>
> --
> Tegger
[snipped]

Could be it is not opening all the way causing the temp to run hot. Using
the heater as a mini radiator helps to lower the temp. Of course that would
also work if the radiator was partially blocked.
 >> Stay informed about: 95 Accord runs hot on freeway 

Tegger <tegger RemoveThis @tegger.c0m> wrote in
news:Xns98BBCB1FB5862tegger@207.14.116.130:

> Jim Yanik <jyanik RemoveThis @abuse.gov> wrote in
> news:Xns98BBC9816FB52jyanikkuanet@64.209.0.86:
>
>> Tegger <tegger RemoveThis @tegger.c0m> wrote in
>> news:Xns98BBBE00C4F5Ftegger@207.14.116.130:
>>
>>> pinkfloyd <none RemoveThis @000.com> wrote in news:965321
>>> _bbd9486094e485fede355cb837e57234 RemoveThis @0000.com:
>>>
>>>> Today I checked every recommendation posted.
>>>>
>>>> First I tried the cold method to check for possibility of bad head
>>>> gasket. I pinched the reservoir hose, and placed my palm on the
>>>> radiator opening. I did not feel any pulsating.
>>>>
>>>> Second, after a long drive on the freeway, when I stopped, I checked
>>>> the reservoir, and there were no bubbles.
>>>>
>>>> Third, while driving on the freeway back home, when the car started
>>>> to heat up, I turned on the heater full blast, and the temp cooled
>>>> down right away.
>>>
>>>
>>>
>>> Then your rad is internally blocked (or the fins have fallen off).
>>>
>>>
>>
>> First put a new Honda thermostat in it.Not some aftermarket TS,a real
>> Honda TS.
>>
>
>
>
> It's not his thermostat. I'm sure of that.
>

at that age,it's certainly suspect.
Besides,just how much heat can the heater core dissipate,if it cools down
his motor? Maybe he's got a worn water pump too.

--
Jim Yanik
jyanik
at
kua.net
 >> Stay informed about: 95 Accord runs hot on freeway 

Jim Yanik wrote:
<snip>
> Maybe he's got a worn water pump too.

pump can't wear in a way that reduces flow - there's no parts that touch.
 >> Stay informed about: 95 Accord runs hot on freeway 

"DodgeDriver" <wingnut RemoveThis @invalid.net> wrote in
news:12qtprqoqflkq20@corp.supernews.com:

>
> "Tegger" <tegger RemoveThis @tegger.c0m> wrote in message

>>
>> It's not his thermostat. I'm sure of that.
>>
>
>
> Could be it is not opening all the way causing the temp to run hot.
> Using the heater as a mini radiator helps to lower the temp. Of
> course that would also work if the radiator was partially blocked.
>
>



Heater core flow is completely independent of the thermostat.

Inlet flow is from the head's outlet end, and outlet flow is downstream of
the thermostat. In other words, the same circulation feeds the heater core
that occurs in the head/block due to the thermostat bypass when the
thermostat is closed.

--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: 95 Accord runs hot on freeway 

Jim Yanik <jyanik RemoveThis @abuse.gov> wrote in
news:Xns98BC6EBF3678Bjyanikkuanet@64.209.0.84:

> Tegger <tegger RemoveThis @tegger.c0m> wrote in

>>
>> It's not his thermostat. I'm sure of that.
>>
>
> at that age,it's certainly suspect.



There's certainly no harm (and lots of good!) in replacing the thermostat
while the cooling system is in dry-dock, but the thermostat is not the OP's
particular problem here. See my other post.



> Besides,just how much heat can the heater core dissipate,if it cools
> down his motor? Maybe he's got a worn water pump too.
>



The heater core is an amazingly efficient heat-dump device. You wouldn't
think so due to its size, but it is. It can very easily compensate for a
rad that can't shed as much heat as it was designed to.



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: 95 Accord runs hot on freeway 

Tegger <tegger RemoveThis @tegger.c0m> wrote in
news:Xns98BCD97CFDB95tegger@207.14.116.130:


>
> The heater core is an amazingly efficient heat-dump device. You
> wouldn't think so due to its size, but it is. It can very easily
> compensate for a rad that can't shed as much heat as it was designed
> to.
>
>
>


But it can't compensate for a thermostat that's stuck shut!


--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: 95 Accord runs hot on freeway