Date: Fri, 13 Feb 2009 17:56:52 -0800
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: Mocal sandwich plate plus oil cooler equals overcooling
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thanks for responding to my comments.
re "but I think I'll pull
> out the compressor tomorrow and have a look anyway. "
"compressor" ???
what compressor ?
oh I get it.......move the AC compressor out of the way to see the water
pump better, is that what you mean ?
did you mean thermostat ?
or water pump .........can't really call that a compressor really, it
doesn't compress anything as liquids are not compressible .
they are a 'little' but not for practical discussion purposes.
I would say an IR temp gun is mandatory to own and use if you're chasing any
coolant or temp issues.
re :
There was boiling upon shutoff, when the coolant stops
> flowing and soaks up heat from the hot metal bits.
Of course you realize millions of cars don't do this when their coolant
stops circulating.
The temp of the coolant in the engine does goes up some yes, for the first
few minutes after shut down......
but it's normally never an issue, and 'boiling' isn't normal.
I know you tried several pressure caps ..........but I'm still not convinced
you don't have a pressure cap issue.
how about this.........
what precisely is the coolant mixture you are using ???
brand , type, and water/a-frz proportion.
I think you said Blue Pentosin.
that should work of course..........
but I wonder ........or no, better way to express it is ' I don't
automatically assume that your coolant mixture is totally not related."
Scott
----- Original Message -----
From: "John Bange" <jbange@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, February 13, 2009 5:38 PM
Subject: Re: Mocal sandwich plate plus oil cooler equals overcooling
>> will try to keep this short.
>> I am under the impression that The Issue is ........
>> it runs at proper cooling system temp,,,,,,,,,but there is bubbling in
>> the
>> coolant pressure bottle.
>
> Precisely! There wass boiling upon shutoff, when the coolant stops
> flowing and soaks up heat from the hot metal bits.
>
>> ( couldn't quite decipher this : "the bubbles vanish as> soon as the
>> his
>> the pressure tank and condense." )
>
> Vanish, as in the bubbles, which are steam, come in contact with
> cooler water in the pressure tank and turn back to liquid.
>
>> tell me this ............does coolant disappear in any way, ever ?
>
> Not a bit, with the exception of the one time at high altitude when it
> was boiling enough to push it to the overflow tank.
>
>> are 'the only symptoms' that the coolant bubbles and the oil is too cool
>> ?
>
> Ah.... I see the confusion. The boiling at engine shutoff prompted me
> to add the oil cooler. The oil cooler completely eliminated the
> boiling problem (by cooling down the bottom end) but due to what is
> apparently a stuck oil thermostat, it is now overcooling.
>
>>
>> in all cases of mysterious unsolvable problems, I say..........go back
>> to
>> the basics.
>> starting with a leak down test.
>
> I haven't had any of the classic symptoms of such leakage ("air"
> appearing in the tank when the engine runs, etc) but I think I'll pull
> out the compressor tomorrow and have a look anyway. It is, after all,
> an easy test to run.
>
>> It is possible to have a water pump that doesn't leak or show any of the
>> common water pump failure modes, and it still fails to pump
>> correctly..........but that is extremely rare. The most likely reason
>> that
>> would ever occur is a odd aftermarket water pump that's not quite built
>> to
>> correct specs in the first place......
>
> Well, since I own two Vanagons and it's time to change the coolant
> again ANYWAY, I will probably just get a new one and replace the one I
> have. It was 3 months old and very shiny when I bought the van, so it
> was technically new when I put the Boston Bob engine in 20K miles ago,
> but it is also of unknown origin..... Given that it can't hurt to
> have a spare water pump around, why not? The more money and time I
> throw at this box, the more it becomes MINE!
>
> Incidentally, I've driven this week with 90% of the cooler blocked
> with a piece of cardboard, and the temperature has been more
> reasonable, indicating right about 180-ish. That probably translates
> to 190-200 actual. An IR temp probe is also on my shopping list. I
> will probably drill and tap the sandwich plate for an oil temperature
> sensor, given how inaccurate the drain plug sensor location has proven
> to be over the years.
>
> --
> John Bange
> '90 Vanagon - "Lastwagen"
> '90 Vanagon GL - "Wiesel"
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