Date: Sun, 26 Feb 2006 09:16:20 -0600
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: Overflow coolant Tank
In-Reply-To: <001701c63ae1$97f3d5b0$6e00a8c0@owner998c7c609>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
George Thorburn wrote:
>Tim wrote;
>
>
>>>My coolant tank is completely full when i take the cap off even a litte
>>>comes out (good I guess no coolant leaks) but my overflow tank is bone
>>>dry...i dont think any coolant is flowing to it...i checked the hose at top
>>>and it is find...the one on the bottom is tough to get off so i left it
>>>alone and it seems fine too?
>>>
>>>
>
>
>
>>>Any thoughts.....thanks in advance
>>>
>>>
>
>Tim,
>Try a new coolant tank cap. They only cost about $10.00 and over time the valve inside ages and does not let excess coolant and pressure get to the overflow tank. This is just speculation but I think that some of the other problems with the coolant system in these vans is caused by excess pressure from old caps. Our van went through two rubber head gaskets, (one on each side) when we fixed the second one we changed the cap and have had no problems since (knock on wood).
>George
>'85 Westfalia
>
>
If I remember correctly, the cap is set for a releif pressure at just a
fraction over 1 atmosphere of pressure. A test would be to begin with a
cold engine, and the overflow tank filled to the min line. Start the
engine and run it until the thermostat opens. Let it continue to run
until the cooling fan comes on. All the time this is going on, watch
that expansion tank. As the engine warms, the coolant will expand and if
the cap is working correctly the coolant level in the overflow tank
should rise. If it does not, rev the engine to 2000 rpm and let it run a
bit, just as if you were bleeding the cooling system, but leave the cap
on the expansion tank. If you still get no rise in the overflow tank, yo
have a bad cap and are over pressurizing your cooling system. With that
happening you are putting a lot of pressure on all the rubber hoses in
the system and they are stretching to accomodate the expanding coolant
and increasing pressure. Not good!!
As there is seemingly no loss since the expansion tank level doesn't
drop, then you should not have any leaks in the cooling system proper.
Just an expansion tank cap problem.
Regards,
John Rodgers
88 GL Driver
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