Jim Yanik wrote:
> Ashton Crusher <demi@moore.net> wrote in
> news:e0miv3tnkhrffh49i9moc8iv12hv679n1u@4ax.com:
>
>> On Fri, 4 Apr 2008 10:56:27 -0700 (PDT), bubbabubbs@yahoo.com wrote:
>>
>>> I've been thinking about what my next commute car is going to be. 80
>>> miles/day, it's just me and my briefcase, so thinking of a small
>>> vehicle with great gas mileage. Yaris hatchback, Scion xD, or Honda
>>> Fit would work for me. Problem is, none of them has a water temp
>>> gauge, just an "idiot light."
>>>
>>> Would you consider buying a car (brand new) that only has the water
>>> temp "idiot light", but no water temp _gauge_ ?
>>>
>>> Btw, do these "idiot lights" come on early enough to prevent major
>>> engine damage, or only after the engine has overheated to the point
>>> where the head gasket is blown?
>>>
>>> Also, the next bigger models that do have the water temp gauge would
>>> be Toyota Corolla, Matrix, or Honda Civic. But the extra purchase/
>>> ownership cost may not even offset the possible repair costs resulting
>> >from a Yaris/Fit/xD engine overheating (which, if happens, would be
>>> several years down the road.)
>>>
>>> TIA,
>>> Bubba
>>
>> Yes, I would. I've had many vehicles with real gauges and a few of
>> them overheated and I never noticed the gauge go up because it
>> happened so fast (blown hose). I might have noticed an idiot light.
>> I'd like to have both in an ideal setup. It's nice to know what's
>> happening with water temp on a long uphill, esp if you are towing
>> something. My 99 Mustang GT has a temp, oil and volt gauge but all
>> are just idiot gauges. At least on the mustang you can put the
>> Dashboard odometer into "diagnostic mode" and it will give a true
>> digital readout of water temp. I think most idiot lights for water
>> temp are set to go on at about 235 degrees. If everything is good in
>> the cooling system it should not boil till it hits 260 degrees.
>>
>
> OTOH,my 94 Integra GS-R had a stuck thermostat,and I noticed the temp gauge
> rising when I stopped and falling to 'Cold' when I was driving. I got the
> parts and fixed it before anything worse happened.
> And the last car I had with only an idiot light blew a rad hose (during a
> Buffalo blizzard) and left me stranded out in the middle of
> nowhere(Millersport Rd),except that a generous person stopped and gave me
> and my bud a ride ALL the why home,quite out of their way. The idiot light
> was useless to me.
>
> Conclusion;idiot lights are for idiots.


in the civic, the temp gauge pointer is calibrated to be flat line from
85C to 100C. that's a pretty broad range with zero needle movement,
especially when you consider the thermostat starts opening at 78C and is
fully open at 90C, and it makes any needle movement other than "hot"
pretty much meaningless - "idiot light" territory.

while i "like" to have a gauge myself, engineering reality is that it
doesn't mean much in this situation and an idiot light would probably be
a better single choice if, like me, you just happen to be distracted and
don't check the gauges and end up cooking the motor one day. a light is
much more noticeable.