Date:         Sat, 24 Jun 2006 14:59:11 -0400
Reply-To:     "Daniel L. Katz" <katzd54@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "Daniel L. Katz" <katzd54@YAHOO.COM>
Subject:      Re: conflicting cooling problem data...(this one is for the true
              experts...)

obviously a bad temp i sending unit.

could prove this by heating in water on the stove and monitoring both
sensor resistance and water temp.

other confirmation would be to test temp ii sensor, which has similar
specified temperature-resistance characteristics.

dan

On Sat, 24 Jun 2006 12:40:29 -0400, robert shawn feller
<carboncow@GMAIL.COM> wrote:

>I've just about had it trying to figure out why my gauge/LED tell me I'm
>running very warm and often "hot" when I'm stopped.
>
>I've got conflicting troubleshooting info everywhere, here is the process:
>
>this spring my temp gauge was running very low. Tests showed a faulty
temp1
>sender unit. I got a new unit from van-cafe.com along with a new stock
>thermostat. Instantly my gauge was now showing high with intermittent LED
>activity (not due to the level). I doubted the gauge so I pulled out my 3M
>Non Contact Thermometer and it shows EVERYTHING seams fine, block and
>coolant hoses are all below 196F. I double checked my fan and its working
>all speeds. van-cafe.com was nice enough to send me another sender unit
>although they doubted there was a failure in the sender. I replaced the
>sender along with another thermostat and guess what, still running hot. I
>owed them $12!
>
>Before I replace the radiator and fan thermal switch as many have
>recommended I wanted to check a few things. R. Mathiew sent me a OHM chart
>showing the resistance at all temps. Now I see a problem unless his chart
is
>wrong.
>With a COLD engine the OHM reading should be 1500-2000 according to his
>chart, but my reading on my FLUKE multitester shows 800OHM, this was
>confirmed with a less professional unit. As the engine warms the chart
also
>shows that the "high" temps should be between 160-220OHM at 212F. All
>readings on the multitester came way to early, I was still able to touch
>hoses when the reading on the ohms said my hand should be burnt. Took the
>van around the block and its been idling for 30 minutes and the reading is
>currently 62.4 OHM which should have my engine block melting. My 3M tells
me
>the hottest pipe from the water pump to the thermostat housing is only
196F
>and hottest spot I can find on the engine block is 192F. The fan has yet
to
>cycle today as it is 82F in Ohio but it has cycled before in hotter
weather.
>I'm quite sure that thermoswitch is working fine.
>
>I built a resistance box to test the dash guage and it works 100% OK. The
>gauge shows the proper locations for a given resistance. I have not
checked
>voltage at the gauge but if my resistance box shows proper numbers I
should
>be OK. Additionally my mutitester readings are showing the same "high"
>readings from the sender unit. So here are my questions:
>
>
>   - Does anyone think I've got to bad sender unit, again? (bad
>   batch/run?)
>   - Could the OHM readings given to me be incorrect? (I'll display them
>   below)
>   - What else can I do before I spend (as some recommend) $200 on a
>   radiator and fan thermswitch, which doesn't make sense to me at this
time.
>   There has been much talk about radiator flow restriction.
>   - Would you not agree that the metal pipe from the water pump to
>   thermostat housing is the hottest water reading for an thermo-gun and
196F
>   is acceptable?
>   - Get a sender from another vendor? (that would make three!)
>
>I know many have stated to check wiring but and increase in resistance
from
>old wiring or bad ground would show a low reading as when my first sender
>failed.
>
>I was told this sender is a standard VDO ohm range so can someone check
>these temp to ohm numbers below. I cannot find data in Bentley or other
>sources.
>
>Lastly I pulled the Coolant Level Warning sender last weekend and I forget
>where it goes in the relay/fuse box. Top row far right?
>
>Temperature sensor resistance
>
>F  (C)                  Ohms
>50  10                    3100-4100
>68  20                    2000-3000
>86  30                    1500-2000
>104 40                    1000-1500
>122 50                     750- 950
>140 60                     540- 650
>158 70                     380- 480
>176 80                     290- 360
>194 90                     205- 280
>212 100                    160- 220
>
>
>Thanks.
>
>--
>shawn feller, ohio
>1986 vw vanagon gl westfalia
>1993 vw eurovan gl
>plus a couple of saabs, boats, jet skis, dog and wife (all require to much
>maintenance, accept the dog)...
>
>www.carboncow.com
>www.carboncow.net