[Vwdiesel] More on coolant flow through radiator

[Erik Lane]

it seems that all the 1.6L diesel water pumps are the
same, at least from the backside. i know that there
are two different size hubs on them, but the pulleys
themselves seem to be the same size.

i just went and looked at the vanagon and crawled
around underneath it as much as i could (it's out in
the field) and i couldn't follow the coolant lines all
the way from the front to the back. i could only see
them at either end. but as long as they don't cross
over somewhere in between it looks like it draws water
from the top of the radiator! so i was probably wrong.
i still think that it's a bad setup and the wrong way
to do it. but oh well.

as far as the vanagon needing more cooling cause it's
working harder, i agree. but a higher volume of
coolant being pumped isn't the only way to have better
cooling. its radiator is possibly twice the surface
area of the smaller cars. so i can get a much greater
temperature drop over the radiator and then the
coolant has more capacity to absorb heat from the
engine. the greater volume would also help in
absorbing any kind of temporary heat spikes, but i
don't think the greater volume would affect long term
cooling to any great degree. the pipes are large
enough (~1 inch) that i don't think for the short
length of the run (only 8ft?) there is any noticeable
restriction as far as pumping is concerned. but i'm
not any kind of expert so i could be wrong there as
well.

"Ergo: sufficient circulation takes care of it."

i would revise that to say that sufficient cooling
takes care of it. with a plugged radiator you aren't
getting enough coolant in contact with the pipes and
from there to the fins which actually transfer the
heat to the air. theoretically you could have a
radiator that was still flowing ok but have the
insides of each pipe coated with some kind of good
insulating gunk. that gunk would keep the heat from
escaping - the engine would overheat. (of course i
doubt that would ever happen in real life - the whole
pipes usually get plugged up i think.) but i would
think that if there was enough junk to clog up some of
the pipes then others would have partial clogs or
coatings and need reaming out.

sorry it took me a bit to get to this. i had to wait
till i could physically go out and check them out.
didn't want to assert something without being able to
check.

erik

--- Sandy Cameron <scameron at compmore.net> wrote:

> At 10:31 PM 02/09/04 -0300, you wrote:
> >The water temperature needle would stay just below
> the LED with the old 
> >wasserboxer and with the diesel it runs just above
> the LED during 
> >normal driving, but when running fast (a relative
> term with a 75 hp 
> >diesel in a 5,000 lb vehicle) on the highway or
> pulling up a long hill 
> >the temperature will rise.  I have noticed that the
> engine and heater 
> >warm up much more quickly with the diesel than the
> gas flat four.  This 
> >I found strange as diesels are not known for fast
> warmups, especially 
> >around town.
> 
> The long circuit may be the problem. I do not know
> if the water pump for a
> diesel engine used in the van is different than the
> one used in cars. I
> would not be surprised.
> 
> I noticed last year (in winter) with my partially
> plugged rad (now flushed)
> that the temp rise in the diesel is directly related
> to how hard you are
> flogging it. Once my rad was clear, it didn't matter
> how hard I flogged it,
> the temp remained constant. Ergo: sufficient
> circulation takes care of it.
> 
> Investigate high efficiency water pumps as applied
> to vans with long,
> restricted cooling circuits...
> And back flush your rad again. If you have just
> assembled a whole new
> cooling system, there may be mice in it somewhere
> (earwigs, crickets, etc
> they're all looking for a home)
> Leave a rad sitting on the ground for one night,
> next morning it's full of
> earwigs.
> (how do I know?)
> 
> Sandy
> 
> _______________________________________________
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> Vwdiesel at vwfans.com
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> 



		
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