Thermostat update and non thermal fan clutch

[charles boyd]

The 180 Mr Gasket thermostat worked as it should on our trip to S.C. Stayed right on 180 till we hit Saluda mt. Stayed on 55 mph going up and temp
did rise to ~190 but not hot enough to engage fan clutch. I had found the new fan clutch I was running was a non thermal unit? It looks the same as
the thermal unit I replaced it with, small spring and all. So what's the deal with a non thermal fan clutch? I never heard the non thermal kick on
with the old thermostat even with temps running in the 200 range. Didn't even hear it on initial start up. Now that I have a proper working
thermostat I can hear the new Delco clutch on initial start up and it quietness down as it should.

--
C. Boyd
76 Crestmont
East Tennessee

 

[johnny]

If it runs at startup and then slowly stops, it is distributing the working fluid properly for a disengaged clutch. If you only got to ~~190, it
probably never saw enough hot air to fully engage.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[terry1]

Maybe your previous t-stat did not flow as much at 200 degrees as the new one does, and the radiator was doing a good job of cooling that lower flow
rate, so the fan clutch 'stat never got hot enough to fully engage and the engine ran warm. At least, according to your gauge that senses the coolant
in the engine, instead of the radiator airflow being sensed by the fan clutch thermostst.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

 

[roy keen]

Are you saying you removed a thermal clutch fan and replaced it with a non thermal unit? If this is the case a non thermal fan will not move as much
air it is designed to be much quieter . It may be ok on the flat lands but it would be a bad idea to have it if you are in the mountains out west
especially if you are towing anything.
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[Jim Hupy]

Many people miss the fact that the fan clutch is activated by hot air from
the radiator flowing over the thermostatic coil spring on the clutch. NOT
FROM THE RADIATOR COOLANT. Those are two different things. Engine coolant
is in a very precise closed environment, pressure controlled, and not
subject to many outside influences. The air flow over the radiator, no
control at all. Ground speed, solar heat gain, headwind vs tailwind, and
many other factors influence the air temp over and around the radiator. So,
expect that there is going to be a different result each time you drive the
coach.
Jim Hupy
Salem, OR
78 GMC Royale 403

> Maybe your previous t-stat did not flow as much at 200 degrees as the new
> one does, and the radiator was doing a good job of cooling that lower flow
> rate, so the fan clutch 'stat never got hot enough to fully engage and the
> engine ran warm. At least, according to your gauge that senses the coolant
> in the engine, instead of the radiator airflow being sensed by the fan
> clutch thermostst.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
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