Date: Sat, 4 Feb 2006 01:27:15 -0500
Reply-To: rsf <feller@CARBONCOW.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: rsf <feller@CARBONCOW.COM>
Subject: Re: running hot....any ideas?
In-Reply-To: <Pine.LNX.4.63.0602031258570.17467@centipede.gpcc.itd.umich.edu>
Content-Type: text/plain; charset="us-ascii"
To the troubleshooting comments:
Any variable resister tool will work and you can use this page from bentley
online to determine what ohm readings will make you gauge "do the right
thing"...
http://www.bentleypublishers.com/tech/vw/bentley.vw1301.testing.htm
Vw in the over engineering uses special tools for everything when sometimes
a far simpler design or tool would have done just fine!
Shawn
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Jonathan Farrugia
Sent: Friday, February 03, 2006 1:18 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: running hot....any ideas?
okay so i gave this whole issue some consideration in the past. so much
so that i did a survey on this list about coolant needle position. here
are the results:
http://gerry.vanagon.com/cgi-bin/wa.exe?A2=ind0402B&L=vanagon&P=R11774
mark drillock can speak much more authoritatively on the coolant light and
gauge system than i. for a 85 there is really two inputs to the gauge the
tank level sensor and the variable resistance temp sender (the one with
only one wire on it. if you look at the bentley they have a cute little
tester to test if the gage is functioning correctly. basically it is a
variable resister that you crank to different locations and then watch
what the gauge is doing. the test where you directly ground the lead to
the temp sensor and watch the gauge peg all the way to the high end is
just an extreme variation of this test.
since the system works on resistance if the resistance in either the
sender, wire, or crimp connection changes the position of the needle will
change. for example you could have a sensor that works fine but some
corrosion inside the crimp of the connector. this corrosion = resistance,
so therefore your gauge would be seeing a higher resistance across all
temperature readings. so without the corroded crimp connector the gage
reads right over the led then with the extra resistance of the corrosion
it might read a little higher.
the real solution to all of this is to either find a dealer that has the
vw special tool and actually knows how to use it. or to figure out how
the tool works ie what resistance equals what position on the gauge, and
or what resistance equal what temperature. this could be done in directly
by using a temperature measuring device and a multimeter on a "properly
functioning" system.
also the gages in the earlier vans (1.9) do go bad as i have had to
replace the one in my. if remember correctly this tends to involve the
light flashing when its not supposed to be flashing. also one other
variable on this system is the voltage regulator in the instrument
cluster. i have never found problems with these as a test i swapped out
two or three of these in my cluster before changing the gage and they did
not affect operation or voltage readings.
one final comment on resistance and gage readings. the resistive
temperature gage is located in a high resistance area. it is in that
little aluminum casting that is held on with two long bolts. in almost
every system that i have taken apart those bolts are heavily corroded.
these bolts are the main ground source for the sensor bolted into that
housing. this also complicates matters of whether the gauge is seeing
accurate resistance readings.
jonathan
On Fri, 3 Feb 2006, JordanVw@AOL.COM wrote:
> i'll be alittle more descriptive..
> this is a '85 transporter, 1.9L wbx, automatic, no air conditioning.
> the problem i was having is that the needle would read on, or over the red
> light location (but not pegged 100%) during normal driving. the red light
was
> NOT on. and no, system was not boiling over. coolant level full in tank.
>
> so i thought ot myself, this may be a clogged radiator, so i installed a
new
> radiator, and thermoswitch on rad.
>
> that didnt help anything..
>
> also installed the good 'ol TK coolant line splice kit at the same time.
>
> anyway, i am upgrading the inst cluster to the later style w/ tach/digi
clock
> and in doing so, will obviously change out the gauge on the dash. so at
that
> point it will have:
> -new rad
> -new thermoswitch on rad
> -"new" gauge in inst cluster
>
> so if all that doesnt help, what is my only alternative? faulty WP?
>
> thanks..
>
> chris
>
>
> In a message dated 2/3/06 12:36:09 AM Eastern Standard Time,
> feller@carboncow.com writes:
>
>
>> Did follow any previous threads on your troubleshooting so forgive and
>> obvious stuff here...
>>
>> Red dot is blinking?
>> Needle is buried on 100%?
>> Are you boiling over?
>> Can you confirm from your experience that anything feels hotter then
usual?
>>
>> If truly NOT hot then...
>>
>> Bad sender
>> Bad Gauge
>> Bad Voltage Stabilizer in gauge cluster (usually fails both gauges from
what
>> I read)
>> Shorted wire will cause 100% reading
>>
>> If TRULY hot...and good heads and you pressure tested the coolant system
>> then...
>>
>> Bad flow due to water not being moved or blockage (you mentioned new
>> radiator) is your answer.
>>
>> Thermostat closed 100% shut
>> Bad water pump (just happened to my jeep, no noise but not 100% efficient
so
>> was over heating)
>>
>> Shawn
>>
>>
>>
>
>
>