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buffered coolant temp guage



 
 
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  #1  
Old August 7th 06, 06:22 PM posted to alt.autos.bmw
Jon Blake
external usenet poster
 
Posts: 4
Default buffered coolant temp guage

Seeking the group's wisdom on this.
Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.

However, I find that the water temp guage is "buffered". That is when,
say, climbing up a mountain road to a pass, many of which Washington State
here in the USA is blessed with, the temp guage never climbs. When
descending long stretches in cool weather the temp guage never makes any
movement to a cooler reading.

I've heard the more than likely apocryphal story that for the USA market
the average bimmer owner was concerned that such a fine car had such
fluctuations in its coolant temp, hence the rock sold reading regardless
of actual engine temp. I pray this story is urban myth.

Anyway, I'm convinced that the guage won't to a damn thing until someday
when something untoward happens and then it will jump into the red. I want
a real guage not an idiot light costumed as a guage.

I am considering adding oil temp, voltage, oil pressure guages mounted
just in front of the shifter in the small space now occupied by an
accesory compartment. I really would prefer not to use one of the guage
spots for a coolant guage.

So, can the buffering be bypassed so as to give real readings, or is the
whole thing so buried in some obscure cpu that there's no hope.

As you can tell I'm an old fart - I've railed before on the lack of an oil
dipstick in this year's models as an example and so am prepared to be
spanked again with some sort of comment about the guage will do what's
it's supposed to do if things get overheated so I shouldn't. :-)


- Jon
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  #2  
Old August 7th 06, 07:46 PM posted to alt.autos.bmw
Tom K.
external usenet poster
 
Posts: 257
Default buffered coolant temp guage


"Jon Blake" > wrote in message
ashington.edu...
> Seeking the group's wisdom on this.
> Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.
>
> However, I find that the water temp guage is "buffered". That is when,
> say, climbing up a mountain road to a pass, many of which Washington State
> here in the USA is blessed with, the temp guage never climbs. When
> descending long stretches in cool weather the temp guage never makes any
> movement to a cooler reading.
>
> I've heard the more than likely apocryphal story that for the USA market
> the average bimmer owner was concerned that such a fine car had such
> fluctuations in its coolant temp, hence the rock sold reading regardless
> of actual engine temp. I pray this story is urban myth.
>
> Anyway, I'm convinced that the guage won't to a damn thing until someday
> when something untoward happens and then it will jump into the red. I want
> a real guage not an idiot light costumed as a guage.
>


This is exactly how the "idiot light" gauge is apparently designed to
behave. I think the oil temp bar gauge on my BMW air/oil cooled motorcycle
actually moves up about 1/64" when the ambient air temp rises from 75o to
100o, but it's a bit hard to judge such miniscule fluctuations. Be happy -
at least your car still has a dipstick and spare tire.

Tom K.


  #3  
Old August 7th 06, 07:47 PM posted to alt.autos.bmw
Pete[_2_]
external usenet poster
 
Posts: 160
Default buffered coolant temp guage


"Jon Blake"wrote
> I've heard the more than likely apocryphal story that for the USA market
> the average bimmer owner was concerned that such a fine car had such
> fluctuations in its coolant temp, hence the rock sold reading regardless
> of actual engine temp. I pray this story is urban myth.


It's quite probable actually. Other manufacturers (Audi/VW for one) have
been doing it for years. The gauge has a dead range, and within this range
the needle is designed to stay put. Only when the coolant temp is
significantly too high/low will it budge. You'd just have to find out what
that dead range is. I'm hoping the engineers aren't as dumb as you might
expect and put some thought into this without endangering the engine.


> am considering adding oil temp


Yeah, that would be a more useful gauge, IMO. My A4 had it and I always
paid more attention to it than to the coolant temp gauge because I wanted to
make sure my oil was warmed up before I drove it hard. Normally the oil
takes a bit longer to warm up as compared to coolant.


> so am prepared to be spanked again with some sort of comment about the
> guage will do what's it's supposed to do if things get overheated so I
> shouldn't. :-)


)

Cheers,
Pete


  #4  
Old August 7th 06, 10:45 PM posted to alt.autos.bmw
John Carrier
external usenet poster
 
Posts: 216
Default buffered coolant temp guage


"Jon Blake" > wrote in message
ashington.edu...
> Seeking the group's wisdom on this.
> Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.
>
> However, I find that the water temp guage is "buffered". That is when,
> say, climbing up a mountain road to a pass, many of which Washington State
> here in the USA is blessed with, the temp guage never climbs. When
> descending long stretches in cool weather the temp guage never makes any
> movement to a cooler reading.
>
> I've heard the more than likely apocryphal story that for the USA market
> the average bimmer owner was concerned that such a fine car had such
> fluctuations in its coolant temp, hence the rock sold reading regardless
> of actual engine temp. I pray this story is urban myth.
>
> Anyway, I'm convinced that the guage won't to a damn thing until someday
> when something untoward happens and then it will jump into the red. I want
> a real guage not an idiot light costumed as a guage.
>
> I am considering adding oil temp, voltage, oil pressure guages mounted
> just in front of the shifter in the small space now occupied by an
> accesory compartment. I really would prefer not to use one of the guage
> spots for a coolant guage.
>
> So, can the buffering be bypassed so as to give real readings, or is the
> whole thing so buried in some obscure cpu that there's no hope.
>
> As you can tell I'm an old fart - I've railed before on the lack of an oil
> dipstick in this year's models as an example and so am prepared to be
> spanked again with some sort of comment about the guage will do what's
> it's supposed to do if things get overheated so I shouldn't. :-)


Truth is that BMW had numerous customer "concerns" because the temp gauge
would reflect the load on the car and ambient conditions. IOW it behaved as
a temp gauge should. So they put in the buffered gauge as a peace of mind
solution for the great mass of the ignorant. Of course you'll now get
little warning of a cooling problem with a gauge climbing inexorably toward
the doom level. Instead everything appears A OK and then a rapid rise to
the peg. You've got about 10 seconds to kill the engine and park it.

BUT, there are several nice aftermarket gauge packages for the E46 that fit
where you specified. A sensor or two to install, route the wiring and
enjoy.

I've seen no DIY mods to the current gauge that will allow it to read
properly.

R / John


  #5  
Old August 7th 06, 10:57 PM posted to alt.autos.bmw
Floyd Rogers[_1_]
external usenet poster
 
Posts: 689
Default buffered coolant temp guage

"Jon Blake" > wrote
> Seeking the group's wisdom on this.
> Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.
>
> However, I find that the water temp guage is "buffered". That is when,
> say, climbing up a mountain road to a pass, many of which Washington State
> here in the USA is blessed with, the temp guage never climbs. When
> descending long stretches in cool weather the temp guage never makes any
> movement to a cooler reading.


BMW temp gauges don't actually read the engine temperature directly.
It displays a readout from the engine computer, which knows exactly
how hot it is from it's sensors. Newer engines even have the computer
controlling the thermostat.

This is all so that the warm-up time is closely controlled and as short
as possible to reduce emissions.

AFAIK, there is no way to "bypass" it without screwing up the
emissions control system.

FloydR


  #6  
Old August 7th 06, 11:57 PM posted to alt.autos.bmw
Jeff Strickland[_1_]
external usenet poster
 
Posts: 419
Default buffered coolant temp guage

You find the ability to maintain the temp within a narrow range a sign of
deception? I'm confident that if the guage is in the middle, then the temp
is within 10 or 15 degrees of where it is supposed to be.

You can **** up your car with aftermarket crapola if you want, but I have no
reason to think that my guages are not accurate when they tell me that all
systgems are nominal.





"Jon Blake" > wrote in message
ashington.edu...
> Seeking the group's wisdom on this.
> Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.
>
> However, I find that the water temp guage is "buffered". That is when,
> say, climbing up a mountain road to a pass, many of which Washington State
> here in the USA is blessed with, the temp guage never climbs. When
> descending long stretches in cool weather the temp guage never makes any
> movement to a cooler reading.
>
> I've heard the more than likely apocryphal story that for the USA market
> the average bimmer owner was concerned that such a fine car had such
> fluctuations in its coolant temp, hence the rock sold reading regardless
> of actual engine temp. I pray this story is urban myth.
>
> Anyway, I'm convinced that the guage won't to a damn thing until someday
> when something untoward happens and then it will jump into the red. I want
> a real guage not an idiot light costumed as a guage.
>
> I am considering adding oil temp, voltage, oil pressure guages mounted
> just in front of the shifter in the small space now occupied by an
> accesory compartment. I really would prefer not to use one of the guage
> spots for a coolant guage.
>
> So, can the buffering be bypassed so as to give real readings, or is the
> whole thing so buried in some obscure cpu that there's no hope.
>
> As you can tell I'm an old fart - I've railed before on the lack of an oil
> dipstick in this year's models as an example and so am prepared to be
> spanked again with some sort of comment about the guage will do what's
> it's supposed to do if things get overheated so I shouldn't. :-)
>
>
> - Jon


  #7  
Old August 7th 06, 11:59 PM posted to alt.autos.bmw
Jeff Strickland[_1_]
external usenet poster
 
Posts: 419
Default buffered coolant temp guage


"Tom K." > wrote in message
. ..
>
> "Jon Blake" > wrote in message
> ashington.edu...
>> Seeking the group's wisdom on this.
>> Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.
>>
>> However, I find that the water temp guage is "buffered". That is when,
>> say, climbing up a mountain road to a pass, many of which Washington
>> State here in the USA is blessed with, the temp guage never climbs. When
>> descending long stretches in cool weather the temp guage never makes any
>> movement to a cooler reading.
>>
>> I've heard the more than likely apocryphal story that for the USA market
>> the average bimmer owner was concerned that such a fine car had such
>> fluctuations in its coolant temp, hence the rock sold reading regardless
>> of actual engine temp. I pray this story is urban myth.
>>
>> Anyway, I'm convinced that the guage won't to a damn thing until someday
>> when something untoward happens and then it will jump into the red. I
>> want a real guage not an idiot light costumed as a guage.
>>

>
> This is exactly how the "idiot light" gauge is apparently designed to
> behave. I think the oil temp bar gauge on my BMW air/oil cooled
> motorcycle actually moves up about 1/64" when the ambient air temp rises
> from 75o to 100o, but it's a bit hard to judge such miniscule
> fluctuations. Be happy - at least your car still has a dipstick and spare
> tire.
>
> Tom K.



Hold the ALT + 0176 (numeric keypad) to create the Degree Symbol ( ° ).





  #8  
Old August 8th 06, 12:04 AM posted to alt.autos.bmw
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default buffered coolant temp guage

In article >,
John Carrier > wrote:
> Truth is that BMW had numerous customer "concerns" because the temp
> gauge would reflect the load on the car and ambient conditions. IOW it
> behaved as a temp gauge should. So they put in the buffered gauge as a
> peace of mind solution for the great mass of the ignorant. Of course
> you'll now get little warning of a cooling problem with a gauge
> climbing inexorably toward the doom level. Instead everything appears
> A OK and then a rapid rise to the peg. You've got about 10 seconds to
> kill the engine and park it.


Sudden overheating problems are usually caused by things like a fan belt
breaking or loss of coolant. And you have warning lights for both of these.
My 'other' car has a normal temperature gauge which when hot reads between
85 and 100C. So that's its normal range. Can't see a problem if a computer
monitors this and keeps the gauge central while within this range.

--
*The modem is the message *

Dave Plowman London SW
To e-mail, change noise into sound.
  #9  
Old August 8th 06, 01:08 AM posted to alt.autos.bmw
JRE
external usenet poster
 
Posts: 93
Default buffered coolant temp guage

Jon Blake wrote:

> Seeking the group's wisdom on this.
> Car is 2005 330Ci, my first bimmer and one I'm enjoying greatly.
>
> However, I find that the water temp guage is "buffered". That is when,
> say, climbing up a mountain road to a pass, many of which Washington
> State here in the USA is blessed with, the temp guage never climbs. When
> descending long stretches in cool weather the temp guage never makes any
> movement to a cooler reading.


This is because you have a mapped thermostat. The water temperature is
controlled so that it increases under light loads and decreases under
greater loads. The way this works is that there is a heating element
wrapped around the usual thermostat element. The computer heats it to
cause the thermostat to open further and lower the coolant temperature.
I speculate that this might be to keep the engine internals within a
narrower range of operating temperatures.

>
> I've heard the more than likely apocryphal story that for the USA market
> the average bimmer owner was concerned that such a fine car had such
> fluctuations in its coolant temp, hence the rock sold reading regardless
> of actual engine temp. I pray this story is urban myth.


The average owner would go bonkers watching the (significant) variations
in coolant temperature. I know how it works, and it would probably
drive *me* bonkers. The gauge is driven such that it indicates in the
center of its range when the operating temperature is within the normal
range.

>
> Anyway, I'm convinced that the guage won't to a damn thing until someday
> when something untoward happens and then it will jump into the red. I
> want a real guage not an idiot light costumed as a guage.


First, I don't know whether it will read high or just jump into the red.
It's not entirely clear to me from what I have read whether they
designed in enough smarts to have the gauge read "higher than normal"
even if it's within the normal temperature operating range. That would
actually be pretty neat, and it would serve much better than a simple
gauge in my no-so-humble opinion.

>
> I am considering adding oil temp, voltage, oil pressure guages mounted
> just in front of the shifter in the small space now occupied by an
> accesory compartment. I really would prefer not to use one of the guage
> spots for a coolant guage.


I recommend *not* removing the existing gauge. The computer knows when
it should read "normal," and you do not.

>
> So, can the buffering be bypassed so as to give real readings, or is the
> whole thing so buried in some obscure cpu that there's no hope.


It's computer-controlled.

>
> As you can tell I'm an old fart - I've railed before on the lack of an
> oil dipstick in this year's models as an example and so am prepared to
> be spanked again with some sort of comment about the guage will do
> what's it's supposed to do if things get overheated so I shouldn't. :-)


It's up to you. But be prepared for significant normal variations in
coolant temperature as the computer adjusts it.

>
>
> - Jon


JRE
  #10  
Old August 8th 06, 01:41 AM posted to alt.autos.bmw
cvstan
external usenet poster
 
Posts: 1
Default buffered coolant temp guage

If you want to see what is going on, install a ScanGauge II or a real
aftermarket water temp gauge. Go to www.scangauge.com. It reads info
from the OBDII connector incuding the water temp. I have one on my
MINI Cooper S (it also has buffered gauges).
My brother has a Jaguar XJ sedan. There was a recall to modify the
temp gauge to keep it from reading real temperature variations.
Apparently service calls were generated by people concerned about the
movement of the gauge.

 




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