Date: Mon, 19 Nov 2012 09:42:22 -0800
Reply-To: Alistair Bell <albell@SHAW.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Alistair Bell <albell@SHAW.CA>
Subject: Re: Rear heater control
In-Reply-To: <20121119100959.3A1OL.210743.imail@eastrmwml106>
Content-Type: text/plain; charset=us-ascii
Dave,
the comparison you make between a car's cooling system:
- closed loop, low O2 (if not anoxic), water, ethylene glycol, corrosion inhibitors
and a dishwasher:
- open loop, O2 rich, water, caustic cleaning solution
doesn't warrant much more thought than just how bad an analogy you made .
:)
alistair
On 2012-11-19, at 7:09 AM, <mcneely4@cox.net> <mcneely4@cox.net> wrote:
> I apologize in advance for anyone who is bothered by pedantry. You don't have to read it.
>
> Of course you are correct, Alistair. But, embedded in the imprecise language is a kernel of value. When a solution like coolant, which has a higher viscosity than does water, and may also contain some materials leached or eroded from various metal components of the coolant system, sits in a stagnant state, it is more likely to precipitate some of those materials creating a greater likelihood of plugging small passageways than when it is flowing.
>
> I clearly demonstrated this when I had a pump go out on a dishwasher just when I was leaving for a three week trip. I just left the water, with detergent and crud in it, in the dishwasher. When I returned, I had to replace more than the pump. The screens and chopper blade were plugged and had to be replaced as cleaning them did not work, though I used a concentrated citric acid solution.
>
> BTW, what is usually called a knob in mechanical applications where it serves as a handle to transfer a circular motion is in fact a kind of lever. An easy way to visualize this is to imagine that a door knob is reduced to a rectangular piece running across its diameter. Then cut off one radius of the piece. What you have is a lever such as has become popular for home doors to reduce strain on hands and wrists of older folks. Many knobs are constructed with a rectangular piece running across one diameter to serve as a handle to make grasping easier. That in fact is what the valve on the rear heater has. This also demonstrates the fact that a knob is simply a lever acting to apply torque.
>
> mcneely
>
> ---- Alistair Bell <albell@SHAW.CA> wrote:
>> "old coolant is terribly corrosive"
>>
>> come on now, how is coolant that is not circulated any older than the stuff that is circulated. I call bull-pucky.
>>
>> alistair
>>
>> On 2012-11-18, at 1:50 PM, Scott Daniel - Turbovans wrote:
>>
>>> There is no 'control knob' ..
>>> there is a lever that you can reach with your fingers, through a hole in
>>> the rear heater cover.
>>>
>>> if the cover is not in place...the poster could be looking at a
>>> knob-like thing ..the bleed valve.
>>>
>>> Bentley would not say much about this leverthat regulates coolant flow .
>>> but the van's Owner's Manual sure does.
>>>
>>> 'Forward' on the lever is 'on'.
>>> Aftward is off.
>>>
>>> I recommend having it at least mostly 'on' all year ..
>>> as having no flow at all, ever, or for very long periods , contributes
>>> to rear heater core leaking ..
>>> a pretty common thing actually. .
>>>
>>> Whether warm air comes out the rear heater is determined by the fan for
>>> the rear heater being on or not, or course.
>>>
>>> you always want at least some coolant flowing through the rear heater so
>>> some fresh healthier coolant is always going through it ...the parts
>>> last longer that way. Old coolant is terribly corrosive.
>>>
>>> Nobody on this list of course...
>>> there are lots of vanagon owners that don't know about the heater
>>> control lever under the back seat.
>>> I was kinda shocked actually to find out VW did it that way.
>>> I can't think of one other car that has a partially heater control under
>>> the back seat.
>>>
>>>
>>>
>>> On 11/18/2012 11:49 AM, Dave Mcneely wrote:
>>>> Harry, that control allows coolant to circulate through the heater core. Summer, off, winter, on. To control air flow, use the knob on the dash. mcneely
>>>>
>>>> ---- Harry Hoffman <hhoffman@IP-SOLUTIONS.NET> wrote:
>>>>> Hi all,
>>>> The heater under the rear seat has a control knob.
>>>> Can someone tell me what it does? The Bentley only shows a picture but not how it functions.
>>>>
>>>> Cheers,
>>>> Harry
>>>>
>>>> --
>>>> David McNeely
>>>>
>
> --
> David McNeely
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