The light will work equally well with 100% antifreeze or 100% water.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of John Rodgers
Sent: Wednesday, February 08, 2006 11:29 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: How to - or not - bleed the cooling system

Ahh!  Enlightenment!

I thought I had a good handle on how that system worked, I stand
corrected.

But you and Larry A. both are saying the circuit provides no warning
when the coolant mixture goes wacko? A warning to tell you to check the
coolant?

Regards,

John Rodgers
88 GL Driver

Dennis Haynes wrote:

>No way is that circuit senstive enough to detect coolant concentration.
The quality of the water supply will have more of an effect on
resistivity than the antifreeze concentration. There is a huge
difference btween hard tap water and de-ionized water. When the ignition
is first turned on the warning should blink for a few seconds as the
bulb check. The circutry for that function is part of the foil circuit
board. Sometimes the timing capactior goes and the light will blink for
a long time. Sometimes the coolant level control relay will go bad
making the light blink forever or never turning it on.
>
>Dennis
>
>----- Original Message -----
>From: John Rodgers <inua@CHARTER.NET>
>Date: Wednesday, February 8, 2006 3:37 pm
>Subject: Re: How to - or not - bleed the cooling system
>
>
>
>>Robert Smythe wrote:
>>
>>
>>
>>>My coolant light flashes at startup, then goes out, temp guage
>>>
>>>
>>never goes
>>
>>
>>>past half. Am I fooling myself in my speculation that its just
>>>
>>>
>>testing> the
>>
>>
>>>function of the circuit with this behavior?
>>>
>>>Robert
>>>90 MV
>>>
>>>
>>>
>>>
>>You are correct.
>>
>>The specs call for a coolant mixture of 50/50 coolant to water. That
>>mixture gives a specific resistance between the two electrodes on the
>>coolant level sensor. Evidently on startup the circuit assumes an open
>>circuit or infinity resistance until the correct voltage for the
>>circuitis read,  at which time the light goes out. If the mixture
>>is incorrect,
>>or the tank is low on coolant and the electrodes exposed, the
>>resistanceis incorrect, the voltage reading is wrong and the light
>>will come on.
>>Important to keep that coolant mixture at 50/50, as well as
>>keeping the
>>tank full.
>>
>>Regards,
>>
>>John Rodgers
>>88 GL Driver
>>
>>
>>
>
>
>
>