Cold engine at 70Mph

Hi all,

I was driving my 91 Honda Accord on the interstate the other day when
it was near freezing outside. I noticed that the engine temperature
was near 'C', even after driving at 70Mph for more than 15min! I had
to turn the heat all the way up to get a comfortable temperature
inside the car. Once I exited the highway and slowed down, the engine
temperature began to rise toward half-way between 'C' and 'H', where
it usually is.

Is the above normal? Is the radiator over-cooling the engine? I am
assuming that a cold engine 70Mph is not good for the car.

Thanks for any advice.

Fijoy

 

The thermostat is probably stuck open.

 

1. it's going to take longer to warm up if the heater is on. in cold
weather, a lot longer.

2. at high rpm's, and thus high coolant flow pressure, it's possible for
the thermostat valve to be sprung open - the effect would be the same as
having the heater on - it'll take longer to warm up.

3. the thermostat might be defective and jammed open. [i've also seen
them with debris/foreign matter jammed inside, again preventing them
from closing properly.] if this is still the original nearly 20-yo
thermostat, i'd recommend changing it.

 

The /thermostat/ is overcooling the engine. You need to replace it.

Use a genuine Honda thermostat ONLY. It's about $30, but well-worth the
money.

 

Hi all,

Thanks for the responses.

I am thinking of changing the thermostat myself, but I am a novice. I
cannot not figure out where the thermostat is, even after a google
search. Is it on the lower radiator hose, or the upper one? Do I
absolutely have to drain the cooling system to change it?

Fijoy

 

Your willingness and sense of adventure are admirable--- but it sounds
like you're over your head on this one. Take it to a repair shop...

 

Yes, my thought, also.

Once you get the antifreeze out, swapping out the 'stat is easy.
Purging the coolant is a pain, at least for me.
--

- dillon I am not invalid

An object's desireability to a dog is directly
proportional to its desireability to another dog.

 

It helps to open the bleeder.

 

Oh sure. Some people want the quick and easy way out.

When I was a kid we had to combine hydrogen molecules with free oxygen
radicals before we could fill our stone radiators.
--

- dillon I am not invalid

An object's desireability to a dog is directly
proportional to its desireability to another dog.

 

The shop manual is your friend. Heck, even Chilton's should get you
through that. I wouldn't advocate trying to rebuild your auto trans
using one, but changint the 'stat should be doable.

Heck, my Honda Fit manual (official) makes it sound easy enough to do
at home.

"Using a chassis lift, raise the vehicle at least three feet.
Disconnect all electrical and fluid lines, remove the hood and, using
an appropriate hoist, lower the enginetransaxle assembly after first
removing the cross member and the tie rods. Then find someone who
knows what the heck they're doing to swear at you for at least ten
minutes and call you an idiot in four or more languages, including
Japanese"

Come one, I just had to. If you read the comic strip "Pearls Before
Swine" you can appreciate the long windup.
--

- dillon I am not invalid

An object's desireability to a dog is directly
proportional to its desireability to another dog.

 

:

See the rad hose that comes out of the /bottom/ of the rad? Follow it up
until it ends. That's where the thermostat is.

Yes, you need to drain at least some coolant.

You should not be attempting this project unless you have some kind of shop
manual, and some kind of mechanical aptitude.

 

You had H and O2 molecules - *luxury*!

 

Thank you all for the replies. They are very helpful.

Fijoy

 

No, free oxygen radicals. Although many were later arrested and
charged for crimes like the riots at Gimburg.

--

- dillon I am not invalid

An object's desireability to a dog is directly
proportional to its desireability to another dog.