Date: Mon, 10 Oct 2011 20:10:21 -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: Thermostats - 87 degree vs 80 degree
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There is..
here's how it works.
it's a 'two door' thermostat.
When it's cold, the main passageway to the radiator is blocked,
and the 'bypass' circuit is open.
that's what that hose on the engine block is for ..
coolant circulates around and around in the engine ( and heater circuit,
which is 'full time' as long as the heater valve is open, and is not
thermostated in any way. All cars are like that )
So at first, when cold, coolant is flowing, but just around and around in
the engine, head, and water pump.
gradually ..
the t-stat starts opening the radiator circuit and closing off the bypass
circuit,
until finally the rad circuit is open however much it needs to be open ..
and when the rad circuit is full open, bypass circuit is fully closed off.
sometimes one may chose to drill a small hole in the edge of the t-stat so
there is always a tiny bit of flow ..
and such a hole can assist in getting rid of air in some
cases...........though usually not in a diesel vanagon.
Not that many people realize that the hose branching off from the Octopus
Hose going to the upper coolant bottle is an air bleed hose, and it's not,
internally, the size it appears to be externally.
There's a restriction in it ..
to allow any air in the engine to be sent to the coolant pressure bottle
where it is separated out.
I have even heard of a profession car shop telling a diesel vanagon owner
that hose needs 'to be clamped off to force coolant forward to the
radiator." Which is totally bogus ..
look at any tdi engine ..........and you will see a small air bleed fitting
and hose coming off the coolant outlet on the side of the cylinder head.
On diesel vanagons ..
they have the same thing, it's just hidden inside the Octopus hose.
Scott
www.turbovans.com
Scott
www.turbovans.com
----- Original Message -----
From: "Karl Wolz" <wolzphoto@Q.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, October 10, 2011 4:14 PM
Subject: Re: Thermostats - 87 degree vs 80 degree
> If I'm not mistaken (I am a lot) there's always some flow, even at lower
> temps.
>
> Karl Wolz
>
>
>
> |-----Original Message-----
> |From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]
> |On Behalf Of mark drillock
> |Sent: Monday, October 10, 2011 4:03 PM
> |To: vanagon@GERRY.VANAGON.COM
> |Subject: Re: Thermostats - 87 degree vs 80 degree
> |
> |I too would only run the 87 degree one but you have the
> |thermostat operation a little wrong. It is not an on/off
> |switch for coolant flow.
> |It merely begins to open at the specified temp and opens wider
> |and wider as it gets hotter. Bentley page 19.11 has the
> |operating range given. Not fully open until 105 C degrees.
> |
> |Mark
> |
> |
> |Dave Mcneely wrote:
> |>
> |>
> |> What the thermostat does physically is remain closed (no
> |coolant flow) when the temperature is cooler than the set
> |temperature, 80 or 87 C. At the set temperature, it opens,
> |allowing coolant flow. It plays no role whatsoever in getting
> |the coolant temperature to drop. It will stay closed until
> |the set temperature is reached, open, and remain open unless
> |the temperature drops below the set temperature. With the
> |engine running in summer that is unlikely. If the engine is
> |overheating in summer (temperature running above 87 C), the
> |thermostat might be stuck closed (not likely), but an 80 C
> |thermostat will not make it run cooler if other causes are at
> |fault (most likely). Check the fan, the radiator, and so on.
> |>
> |> Given that the engine is engineered for 87 C, it should run
> |at that temperature.
> |>
> |> mcneely
> |>
> |-----
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