Larry, this topic has been covered heavily on the Vanagon list over the
years. With your year Vanagon, it is very unlikely to be the sensor in
the coolant tank. It is much more likely the problem is the temp gauge
itself. I have replaced 7 or 8 temp gauges for this in 85 and newer tach
equipped models. There are some added electronics inside the gauge. The
job of the electronics is to flash the led a few times on startup and
then go out unless an over temp or coolant low situation occurs. The
electronics gets flaky with age and flashes the led when nothing is
wrong.

There is an easy test that eliminates the possibility of it being the
coolant level sensor or its wiring and logic.

There is a relay in the main relay panel that monitors the coolant level
sensor and then tells the gauge to flash the led if low.

Pull this relay and see if the problem is gone. If the problem goes away
and stays away, the coolant level circuit is indeed at fault.
If the problem persists with this relay pulled, the gauge or instrument
cluster wiring is at fault.

On 86 and newer this relay is in relay position 3 and has a large "43"
stamped on the end.

Mark

Larry Chase wrote:
>
> Volks,
>
> Two days ago a small problem developed.
>
> The coolant level LED on the temp gauge now takes 5-20 minutes of
> driving before it stops flashing.
>
> The Coolant Temp is in normal operating range ... no change.
> The Coolant Overflow Tank is full to the brim.
> The Coolant Refill Tank is at proper level.
>
> I'm guessing it may be a bad coolant level sensor.
>
> Any other ideas?
>
> Larry Chase
> Email: RoadGuy@RoadHaus.com
> Web: WWW.RoadHaus.com
> Cell:  408.202.1217
> What: North American Road Trip
> How: RoadHaus - 1990 White VW Westfalia Syncro
> Today: Florida
>
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