Date: Thu, 21 May 1998 16:20:12 EDT
Reply-To: GMBulley <GMBulley@AOL.COM>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: GMBulley <GMBulley@AOL.COM>
Subject: The long answer, was: engine run cooler w/ heater on full-blast?
Content-type: text/plain; charset=US-ASCII
In a message dated 98-05-21 14:49:51 EDT, turinsky@JUNO.COM writes:
<< snip>> I've notice that I can get the coolant temp. needle to drop
about a needle's width by cranking the heat to FULL. The needle will drop
even a little further if I turn both fans on full. Why is this? Anyone
have any ideas? I've never heard this topic come up on the List before. I
like having a cool engine, but I getting roasted in the Westfalia! >>
Kevin--
Your question is pretty simple. Allow me to give a long, explicit answer (as
usual?). : )
Imagine under any circumstance that your motor gives off a quantity of waste
heat we will call "100%". Normally, in summer, the cooling system of your van
tries to discard all 100% through the radiator. Sometimes (under light load,
cool outside temps) it is successful at discarding all of the waste heat, and
your motor runs dead center on the operating temperature.
Other times, (heavy load, hill climbing, high outside temp) the cooling ssytem
is insufficient to discard all 100% of the waste heat. Your temps climb to the
upper end of the operating temp range. If VW has done its homework and you
have maintanied your vehicle, you will never see the bliniking light and
pegged needle that tells you "I just can't get rid of enough heat...shut me
down!"
By turning on the heaters in your van you add one (or two with the back
heater) radiators (s) to the cooling system. That's right. Your heater cores
are nothing but little radiators, with fans pushing the heat into the
passenger compartment. As you can imagine, when you add two radiators to the
cooling system, you increase the capability to shed the waste heat of the
motor. Thus your temps drop. A handy thing to remember when the chips are down
and it is 102 degerees outside.
A word of caution, however. Your motor WANTS, no NEEDS to be at a certain
operating temperature. Otherwise it is less efficient, and the fuel injection
system will compensate, and try to "warm up " the motor by dumping a little
extra fuel. I the lower 48, this may not be much of a problem. In Alaska,
maybe.
I don't know enough about gasoline engine operation in extreme cold to tell
you it is okay to block a portion of you radiator. I do this on my TD Jetta in
the dead of winter, but again the thermals and needs of a diesel are VASTLY
different from a gasoline motor. If you want to stay toasty warm, and keep
your motor warm too, research radiator blocking tarps in your area and find
someon who REALLY knows their stuff about extreme cold and blocking cooling
air flow.
best of luck
gmbulley
cary, nc
86 degrees & sunny
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