Date: Sat, 24 Jun 2006 12:40:29 -0400
Reply-To: robert shawn feller <carboncow@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: robert shawn feller <carboncow@GMAIL.COM>
Subject: conflicting cooling problem data...(this one is for the true
experts...)
Content-Type: text/plain; charset=UTF-8; format=flowed
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
