Honda Car Forum

From Click & Clack in the San Jose Mercury News for Friday 7/2/2004:

"Q
I'm having a problem that just started recently. When I start the car,
it takes a while for the engine to warm up. If I sit there, eventually
the temperature gauge will go up to normal. But once I start driving, it
goes back down to "cold", and cold air comes out of the heater. Turning
the heat on causes the engine temperature to drop even faster. It is
freezing in the car! I took out the thermostat and tested it, and it is
working properly. I changed the heater core, too, and the water pump is
new. Can you tell me what else I can look for or test?

Joe

A
TOM: Well, look for that thermostat that you tested and then
reinstalled. Because that's what's causing your problem.

RAY: I agree. You can test a thermostat by putting it in a pan of water
and heating it up. You use a thermometer to see at what temperature the
thermostat closes and opens up, and then you match that to the
thermostat's ratings. And I take it yours passed the test.

TOM: But thermostats are finicky. They can work intermittently. And they
can be "lazy", and open or close only some of the time. Besides, since
the average thermostat costs eight bucks, we ALWAYS replace the
thermostat first if the symptoms point in that direction.

RAY: Your thermostat is stuck in the open position, and it's never
letting the engine get up to operating temperature.

TOM: So your coolant is always circulating through the radiator. And
when you drive, cold air blows across the radiator and cools it off even
more.

RAY: Running the heat cools off the engine, too, since the heater core
is really another small radiator.

TOM: So, pop a new thermostat in there, Joe, and your problems should be
solved. And chalk up the cost of the new heater core you installed to an
expensive lesson in how to work upside down while lying under a
dashboard.

Ron wrote:
>
> Randolph <trash@junkmail.com> wrote in message news:<40C63BFC.794648E7@junkmail.com>...
> > It seems your thermostat is stuck open. Cheap part to buy, but I don't
> > know how easy it is to replace on on your car.
> >
> > Ron wrote:
> > >
> > > I have a 95 Accord with 70,000 miles on it.
> > >
> > > The temp gauge usually runs about a quarter of the way up from cold, now
> > > for some strange reason the gauge stays right on the blue (cool) part of
> > > the gauge.
> > >
> > > I just noticed it doing this 2 wks ago, I live in Florida so I always
> > > keep an eye on the temp gauge in the summer, especially while in stop
> > > and go traffic.
> > >
> > > Sometimes it will barely move above blue area to the line but thats it.
> > > If I turn the heater on it drops all the way down below the blue area
> > > and it blows out *warm* not *hot* air so this rules out a bad sending
> > > unit.
> > >
> > > Does anyone know what could be causing the engine to run so cool?
> > >
> > > Also, no work or preventive maintenance has been performed on the engine
> > > recently that might some how cause this problem.
>
> I finally got around to checking the thermostat today and it is not
> stuck open.When I took it out, it was closed. So I tested it several
> times in a pot of boiling water on the stove and it opens and shuts
> without any problem. Any other thoughts on what could be causing the
> problem.