Date: Mon, 17 Apr 2000 20:21:53 -0500
Reply-To: John Rodgers <inua@HIWAAY.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@HIWAAY.NET>
Subject: Re: Flashing dash LED
Content-Type: multipart/alternative;
Andrew, you are going to get a lot of response on this one.
The flashing light is the "low coolant level warning light".
You have two water tanks in the coolant system. They are in the engine
compartment. There is the coolant expansion tank, and the coolant overflow
tank. The expansion tank is an active part of the system and when the engine
is running coolant circulates through expansion tank. In the top of the tank
is a sensor with two electrodes or prongs that stick down into the coolant.
As long ast the coolant is above the tips of the electrodes, a tiny current
can pass between them, keeping the LED light on the dash in the "off" mode.
If the coolant gets low, the circuit is broken, and the light comes on
blinking, telling you to add or at least check the coolant level.
As a self test, the light comes on at engine start, will blink for a time and
then go out. That is proper operation of the light. On occasion the LED will
come on during driving. If the coolant is very hot, the light comes on, and
it will come on if the coolant/water mix is not 50/50. And it will come on if
there happens to be a little trash caught on one of the electrodes.
The coolant system is a closed system, and includes the expansion tank. As
the coolant warms up it expands. The expanding coolant must go somewhere, so
the pressure cap on the expansion tank opens, and vents coolant into the
overflow tank. Once the engine is off and is cooling down, the coolant
shrinks, a suction occurs, and the coolant is drawn back into the expansion
tank.
I have found that replacing the sensor and the thermostat every year
contributes to good health of the cooling system.
Hope this helps.
John Rodgers
"88 GL Driver
Andrew Grebneff wrote:
> I've never been able to work out what the flashing red LED in my 84
> Caravelle's instrument cluster is for. It starts flashing on startup, and
> goes out some time later. A couple of times it's come back on while
> driving, but doesn't seem to be warning of high coolant temperature.
>
> What IS this LED for? I don't have a owner's manual and that paragon of
> incompleteness the Bentley manual doesn't mention it.
>
> Andrew
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