Date: Sat, 27 Jan 2001 18:37:17 -0800
Reply-To: Mark Drillock <drillock@EARTHLINK.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Drillock <drillock@EARTHLINK.NET>
Subject: Flashing Coolant Light, mysteries revealed!!
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As some on the list may remember, there recently was a thread regarding
a reported difference in behavior of the flashing coolant LED from one
Vanagon to another in response to a low coolant level. I can now report
the answer to this mystery. There are 2 (maybe even 3) different
"coolant level low control units" that control the behavior of the LED
when a low coolant level condition is detected in the main tank.
The original version is part number 251 919 376.
The later (85+) version is part number 191 919 376.
Both versions start flashing the LED about 10 seconds after a low level
condition is detected but then they have 2 behavioral differences.
Difference 1.
The original version flashes but also makes the temp gauge needle rise
to the very HOT end of the scale.
The later version flashes the LED but still properly displays the actual
temp of the engine as sensed by the coolant temp sensor.
Difference 2.
The original stops flashing and resumes normal gauge needle operation
about 20 seconds after the low level condition is corrected.
The later version continues flashing after the level is corrected and
only resets after the ignition key is turned off and back on.
Any year watercooled can have either part number as they interchangeable
other than the differences noted above. I think the later model is to be
preferred as I want to know the reason the LED is flashing. The flashing
LED has 2 meanings. If the engine temp rises high enough it flashes to
draw your attention to the gauge. If the coolant level in the tank is
low it flashes to warn you to check it. With the original control unit
you can't tell which problem you have. I would want the later version so
I would know if the engine was HOT so I could stop ASAP. If it was only
indicating a low level but still a normal temp I would know I could wait
a little while to find a place to stop and check it.
Mike Snow and I tested both of the above parts in a 1983 with a clock
and large temp gauge in the dash.
Then we tested both of the same parts again in a 1987 with a tach and
the smaller temp gauge.
The behaviors completely followed the control units and the year and
type of dash did not matter.
There is a 3rd version referred to in the Vanagon parts documentation as
superseding the others in 1989. It is the later number with a "C"
added. 191 919 376 C. We did not have this unit available to check.
Mark