Answer to first question:  $1.80 .  I've tried cleaning the pins in the
past with limited success.

Answer to second question:  Distilled water with Peak Global Lifetime
antifreeze, flushed and replaced every 4 years.

Additional note to first post:  The level indicator system works
perfectly after replacement of sensor.

On Thu, 16 May 2019 22:04:09 -0400, Larry Alofs <lalofs@GMAIL.COM>
wrote:

>I don't understand why anyone would replace a coolant level sensor,
unless
>it was broken and leaking.  The prongs can simply be cleaned, shined
with
>sandpaper if you like.
>  Are you using a particularly corrosive coolant mixture?  Distilled
water
>or water from a dehumidifier is a good thing.
>
>Larry A.
>
>
>On Thu, May 16, 2019 at 3:28 PM email99@nc.rr.com <email99@nc.rr.com>
wrote:
>
>> I have, once again, replaced the 251 919 372 Coolant Level Sensor to
fix
>> the blinking red light in the Coolant Temperature Gauge in my '86
>> Westy.  It is most annoying that this excessively high priced
sensor has
>> to be replaced on a regular basis.  Certainly VW could have figured
a
>> way to measure coolant level rather than with this sensor.  I have
had
>> to replace this sensor regularly about every 10 years and the cost
has
>> now reached the exorbitant level of $1.80.  The list price from one
>> vendor is actually $42.44.
>>
>> When replacing the sensor this time I made an observation that might
>> help us all avoid this expensive repair.  When the old sensor was
>> removed I noticed one of the sensing pins was bright and clean while
the
>> other was black and rough.  Since the level gauge measures
resistance
>> between the submerged pins there must be a constant small current
>> passing through the coolant between the pins.  This constant
current may
>> be removing ions from one pin and depositing them on the other, thus
>> changing the electrical activity of the surface of both.  After 10
years
>> the difference might be enough to fool the electronic circuitry and
>> cause a false positive blinking light.
>>
>> Has anyone else noticed this difference in appearance of the used
sensor
>> pins?
>>
>> I suggest that the electrical connections to the sensor be reversed
on a
>> regular basis to keep the pins in equal, clean condition.  The
>> electrical plug is not keyed to fit in the sensor so this is an easy
>> thing to do by rotating it 180 degrees.  Doing this often will not
be
>> detrimental so maybe at each oil change would be easy to remember.Â
Or
>> maybe just do it once now and forget about it.
>>
>> Just my Vanagon experience today.
>>
>> Ed
>>