Viscous fan drive

On or around Tue, 05 Oct 2004 21:22:02 +0100, Richard Savage
<[email protected]> enlightened us thusly:

>
>
>Austin Shackles wrote:
>
>>iffy thermostat.
>>
>>actually, saying that, which engine?
>>
>>the Perkins Prima Di I had in a minibus some while back would, if left
>>idling in cold weather with the heater on, drop down to C on the dial. The
>>heater actually provided more cooling than the idling engine created heat.
>>
>>I took the fan off that one altogether with no adverse effects. No turbo on
>>it mind.
>>
>>
>
>RRC + 3.5 V8i and new thermostat!
>
>I wondered if the shroud on the viscous fan setup actually restricted
>the airflow; i.e. the engine block and fan sort of sits in the narrow
>bit of the shroud and perhaps slows the air through the rad ensuring
>that it doesn't cool at it's maximum potential. Engine doesn't overheat
>because of the viscous fan. Removing the viscous fan and it's shroud
>results in a less restricted air flow through the rad resulting in the
>rad being able to overcool the engine.
>
>Richard ;-)

I know sister's BF had trouble on a 3.9 with not enough airflow - he was
towing a heavy trailer though as well. took the aircon rad out in the end,
resulted in much more airflow and no overheating.

have to admit, overcooling is not something one normally associates with
V8s.

On or around Tue, 05 Oct 2004 21:13:38 GMT, Alex <[email protected]>
enlightened us thusly:

>
>>When I replaced the viscous fan on my RRC I was told by the bod that
>>services it that you can stop a viscous fan spinning on a cold engine
>>with finger pressure alone. But he then added that you do this by
>>griping a blade BEFORE starting a cold vehicle.
>>
> The safer method being stick a carrot into the blades. If it's
>working properly it should slice the carrot, if it's not turning
>effectivly the carrot will stop it.
>
>Personally I hate viscous fans, too unreliable, and no backup when
>they do fail.

same's true of electric ones, in the latter point, though. A fixed
engine-driven fan is the most reliable of the lot.

and the electric one has in fact more potential failure points, cos the
switch can fail. I spose you can always bypass it if it doesn't come on, as
a short-term solution.

Austin Shackles wrote:

>I know sister's BF had trouble on a 3.9 with not enough airflow - he was
>towing a heavy trailer though as well. took the aircon rad out in the end,
>resulted in much more airflow and no overheating.
>
>have to admit, overcooling is not something one normally associates with
>V8s.
>
>
>

Completely agree that overcooling is a rarity in the V8s. I'm not
inclined to resolve it though as I wish to dispose of the beast ASAP!

Richard