Date: Wed, 2 Sep 2009 13:09:40 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: 84 coolant light.
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hi,
there are two plastic coolant bottles on watercooled vanagons.
Various terms are used to descibe each.
the more important one, is the one located inside the engine compartment (
like remove the engine cover to get at it ) and it has the pressure cap on
it.
I like to call that one the Pressure Bottle.
Others call it the expansion tank, or expansion bottle.
the one by the license plate - I like to call that one the overflow bottle,
or license plate bottle.
It holds coolant that comes out of the pressure bottle as the coolant
expands from getting hot.
there's a little valve in the pressure cap just for this.
When things cool down, and the coolant contracts ......it sucks some back
from the license plate ( or overflow ) bottle back into the pressure bottle.
If there is a leak anywhere....
the valve in the pressure cap should suck all the coolant out of the license
plate bottle , until it's empty, trying to keep the main part of the system
full.
It doesn't always work that way , but it should.
The pressure caps on the pressure bottle are known to not always be that
reliable - even new ones sometimes. It's good to have a spare new cap
around.
the pressure bottle should stay pretty full. An air space on the top of it
is normal, like an inch.
The license plate bottle has a 'max' line on it.
you can 'overfill' that bottle if you try hard enough. If you fill it right
to the bottom of the hole where the cap is , with everything cold ..........
as things warm up, that level will rise, which is fine and normal.
If you get things really, really warm on a good hot day......it can expand
enough to push coolant out a 'relief hole' at the top of the licnese plate
bottle- making it look like you are leaking coolant, but you're not really -
it just got overfilled. So ......go by the 'max' mark on that bottle.
I also find that many vanagons use a tiny bit of coolant out of the license
plate bottle. Like a cup's worth in a month or two.
I really would like to fit a coolant pressure guage to a vanagon sometime.
I got the idea from subaru engine conversions - there's at least one guy who
did that.
Such a guage would be very useful - since if pressure gets really
high.........that tells you things are hot, but the pressure cap is
maintaining pressure like it should.
If pressure gets above what the pressure cap is rated for ..........that's
not right, and it would be good to know that's going on.
If pressure goes down .......to below pressure cap pressure ( about 14
psi )
then you think about a leak, or air or exhaust getting into the cooling
system.
Just another way to monitor cooling system function.
The sooner you know something isn't really right, the better. The cooling
system on watercooled vanagons, is by far, the system that can fail in
dozens of ways, there are cooling system parts thourghout the entire van,
and many of those are 25 years old .......the more you can do to monitor
what's going on , the better, cause the cost of not catching a problem early
can be rather high.
Vanagons are about 10 times as challenged in the cooling system department
than front engine, front radiator cars are. So they need much more
attention and care to work well and reliably, than most cars do.
But we love 'em like crazy anyway ! There's just nothing else quite like
them.
Scott
----- Original Message -----
From: "Steve Williams" <sbw@SBW.ORG>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 02, 2009 6:38 AM
Subject: Re: 84 coolant light.
> At 08:36 PM 9/1/2009, Scott Daniel - Turbovans wrote:
>>...the level is up where it belongs in the coolant pressure bottle,
>>not the license plate bottle, right ?
>
> Err ... I'm not sure what that refers to. I have an '84, too. No
> trouble with my coolant light, but I'm curious to know more about the
> "coolant pressure bottle." Location? Purpose? "Level"?
>
> Thanks!
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