On the first water-cooled Vanagons the blinking LED was used ONLY to get
your attention when the temp gauge went to very HOT. There was NO low
coolant sensor in the main coolant tank.

Later the coolant tank level sensor was added and VW decided to use the
same flashing LED to warn the driver of a low coolant level. The low
level sensor works by triggering a small control module (in the dash)
when it senses low coolant. This control module then sends a fake HOT
signal to the coolant temp gauge which then makes the LED start flashing
and the needle go to full HOT.

So, in 83+ Vanagons the LED has 2 distinct functions. HOT or LOW
coolant.

To make the whole subject even more complicated, during the 1985 model
year a different low coolant level control unit went into production.
The newer type still flashes the LED when the coolant level is detected
low but does NOT make the temp gauge needle go to full hot.

This has all been previously explained by me and others but it comes up
repeatedly .

Mark Drillock

Dart 330 wrote:
>
> Well I am glad it is not my pump, but I now have a question regarding the
> coolant warning light. I thought the light went off if your coolant level is
> low in the tank, thats what the sensor on top is for. So if an air bubble
> gets inside and the sensor freaks out saying it is low on coolant why would
> the temp needle go sky high. Is some part of the coolant system actually
> getting that hot, or is the computer just trying to get my attention?
>
> Nathan
>
> >Sounds like air in the cooling system - had the same thing happen to me a
> >few years ago.
> >
> >Check your coolant level and top it off. Then bleed the system of any air
> >that might be trapped in the system.
> >
> >TomC
>
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