Atwell, I think I agree with you that it is unnecessary to run the fan after
turning off the engine. But if you really wanted to do it I would connect
it to the sensor on top of the radiator. That is exactly what that does,
except it runs only with the ignition on. I double your sentiments about
bad relays causing problems as I just spent weeks rebuilding a harness
caused by a problem with that particular relay.
Patrick Bowen
-----Original Message-----
From: Atwell Haines [mailto:carbuff@nac.net]
Sent: Monday, May 24, 1999 7:42 AM
To: Gregory W. Smith; spitfires@Autox. Team. Net
Subject: Re: Normal operating temp...
At 02:02 AM 5/24/99 -0400, Gregory W. Smith wrote:
>
>I just installed a mechanical temp gauge and show about 190 while driving,
>and "heat soak" to about 220 after turning the car off (since the gauge is
>mechanical, it keeps reading)
>
>Should I hook up the electrical fan through the thermostatic switch to be
>"Always on" so if the temp's over 190(?) or whatever the thermostatic
switch
>is set at, the fan will blow... much like modern cars that will run the fan
>for a while after the car is turned off?
I wouldn't bother. The fan will only cool the water in the radiator after
the engine is off...remember it's the water pump that actually circulates
the coolant to the engine.
The cars you mention had sensors for the fan in the bottom of the radiator.
On the '80 Spit the sensor is on the cylinder head. So that fan would run
a LONG time after shutdown.
And, if the fan thermostat (or relay) fails, it's dead battery time. ("Sir!
Did you know your car was still running for two hours?")
IMHO normal heat soak isn't a problem on all-iron engines anyway.
Cheers,
Atwell Haines
'79 Spitfire
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