Andy,
The hot water coming out of the engine would hit the switch without allowing
the radiator to work yet, so it might start at a given temperature, whereas
it might not need to, if the radiator can cool it down before it gets into
the engine. I guess it would still be OK as the overall engine temperature
going up would turn the fan anyhow.
On a hot versus cold day the need for the cooling fan is different because
the radiator can take out more heat on a cold day due to the greater
temperature differential. With the sensor on the top the fan would activate
at say 195°F, whereas it might not have to. A bottom sensor would "realize"
it didn't need the fan, because the colder temps would have already dropped
the coolant temperature. This isn't a big deal, but I think the bottom
would be better.
Andy, now that you mention it, by 1988 SAAB 9000S has it on the hot side or
"top" of a cross flow radiator. The question is.... Is this yet another
SAAB weird quirk, or a better way to do it? It does provide for better
cooling of the engine AFTER shut down.
Now I'm beginning to think it really doesn't matter, as the overall water
temp of the coolant will rise slowly anyhow. If the top sensor is high
enough, it won't go on until the radiator can't do it's job anyhow. Anybody
know this answer?
Jack
>-----Original Message-----
>From: Andrew Mace [mailto:amace@unix2.nysed.gov]
>Sent: Monday, February 01, 1999 1:31 PM
>To: Jack Brooks
>Cc: Triumph List
>Subject: Re: Electric cooling fans
>
>
>On Mon, 1 Feb 1999, Jack Brooks wrote:
>
>> Whoops! Thanks, Michael Porter for reminding me of the obvious.
> The switch
>> can't go at the top. It won't do any good.
>>
>> Jack
>> ------------------------
>> I am in the process of converting my TR3A to an electric fan. I
>am unsure
>> about the best place to put the thermostatic switch. I will be using a
>> modern switch (18mm threaded?). I am considering putting it in
>either the
>> bottom or top of the radiator or possibly the steel coolant pipe
>which runs
>> up from the bottom of the radiator up to the block....
>
>Just curious: why can't it go at the top? Seems to me that my old Saab 99
>had its switch at or near the top of the radiator? Of course, I won't go
>into detail about how wonderful THAT system was.... ;-)
>
>--Andy
>
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>* Andrew Mace, President and *
>* 10/Herald/Vitesse (Sports 6) Consultant *
>* Vintage Triumph Register <www.vtr.org> *
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