From: aas7@po.CWRU.Edu (Andrew A. Spencer)
Newsgroups: rec.autos.vw
Subject: Re: Keeping Your Watercooled VW cool.
Date: 17 Nov 1992 06:00:12 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: aas7@po.CWRU.Edu (Andrew A. Spencer)
NNTP-Posting-Host: slc5.ins.cwru.edu


In a previous article, christos@wucs1.wustl.edu (Christos Papadopoulos) says:

>In article <1e95p6INN51b@usenet.INS.CWRU.Edu> aas7@po.CWRU.Edu (Andrew A. Spencer) writes:
>>
>>In a previous article, amiller@almaden.ibm.com (Alex Miller) says:
>>
>>>Running the fan all the time would lengthen the time it takes
>>>for your engine to reach normal operating temperature - during
>>>this time your performance will suffer and you'll pollute more.
>>
>>ok boyz and girlz..not to argue either view point, as i find this
>>to be fairly informative, and i have my opinions, but no specific
>>reazonz for what i do..so..i want a question answered...see..i
>>would argue (if i were arguing) that what brother miller has said
>>above is not true, as this is what the thermostat controlls...
>>if the water is being coooled too much by a constanty running fan,
>>the thermostat does not open as much....this is why trucks, and 
>>various other vehicles of even today that have the fan attached
>>directly to the crank manage to still warm up,etc...like i said,
>>though, i am not sure that this is how a thermostat works...can
>>anyone help me here?(sorry A. Miller, but i just have to ask this
>>but do not wish to dispute what you have said, so please, not to
>>take this as a personal flame!)
>>thanx one and all!
>>DREW
>
>	I too think that Alex's reasoning maybe flawed during
>correct engine operation. Let me explain: In VWs (and most
>cars for that matter) there are two passages that circulate coolant
>through the engine: (1) through the radiator, and (2) through a bypass
>hose. The latter completly bypasses the radiator and is used when the
>engine is cold. This allows the engine to rise to normal operating
>temp very fast. After that the thermostat opens slowly letting in cold
>coolant from the radiator. As the temp keeps rising the thermostat opens more
>allowing more coolant from the rad to circulate through the engine.
>Finally, all of the coolant flows through the radiator and the bypass
>hose is bypassed. Thus the expansion of the thermostat accomplishes
>two different things: (1) opens the radiator passage, and (2) closes the
>bypass hose passage. The two are complimentary, i.e. when one is fully
>open the other is fully closed and vice-versa.  The water pump is unaware
>of which passage is used.
>
>	If the fan runs constantly it cools only the radiator coolant
>during startup, thus not affecting the rate the engine warms up. As
>Drew pointed out, the only side effect is that the coolant in the radiator
>gets colder, but this simply causes the thermostat to open less, thus
>still maintaining the correct engine temp. However, it is possible that
>there might be some coolant leakage from the radiator during warmup
>if the thermostat is old and does not seal very well, in which case running
>the fan constantly will cause slower engine warmup.
>Alex's point is valid in this case.
>
>	Hope this helps.
>
>Christos.
>

this is what i, too, was thinking. thank you for being more clear and
precise than i.
DREW
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