Mystery fan
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Joined: Dec 2006
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From: Bisbee Arizona
Mystery fan
Mounted between the clutch-driven engine fan and the radiator of my '79, is a second fan. It is shallow, the vanes within a ring about 1-1/2" deep, apparenty free turning- not powered, the vanes spin freely- and mounted from its center to the stock shroud by metal spokes- evidently stock, not an aftermarket item.
I cannot find anything about it in manuals, neither my buddy's '70 nor his brother's '76 has anything like it.
Anyone know what the story is about this?
I cannot find anything about it in manuals, neither my buddy's '70 nor his brother's '76 has anything like it.
Anyone know what the story is about this?
Safety Car
Joined: Jun 2004
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From: Beecher Illinois
79 and 80 L82/Air Conditioned Vettes got the auxzillary electric fan.
There's also a flap or trap door in the bottom of the fan shroud.
The 79 also got the rubber extensions on the lower air dam(spoiler).
There's a thermo switch mounted in the pass side head between the rear 2 sparkplugs. Turns on at I think 238 degrees. I have never seen mine run.
Fuse is located in the very lower left corner of the fuse panel.
I think all 81/82s got the fan, but not the trap door.
There's also a flap or trap door in the bottom of the fan shroud.
The 79 also got the rubber extensions on the lower air dam(spoiler).
There's a thermo switch mounted in the pass side head between the rear 2 sparkplugs. Turns on at I think 238 degrees. I have never seen mine run.
Fuse is located in the very lower left corner of the fuse panel.
I think all 81/82s got the fan, but not the trap door.
Last edited by KapsSA; Apr 28, 2011 at 01:32 AM.
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Joined: Dec 2006
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From: Bisbee Arizona
Thanks, great info. Mine is an L82 with a/c, but shortly before it went into storage several years ago I had a rebuilt 4-bolt main dropped in, long story but I'm finding a bunch of shortcuts the mechanic took, the thermo switch I'm sure never got connected. Mystery solved, I know where to start. Thanks again.
Team Owner
Joined: Jan 2006
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From: Crossville TN
I suspect that fan is there to operate after you shut down the engine. After shutdown, the engine block residual heat can raise coolant temps considerably. This 'auxiliary' fan could run after shutdown to keep the coolant from boiling or puking out coolant on the ground. It was likely the "precursor" to fully electric fans which can operate the same way.
Race Director
Joined: Jul 2001
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I suspect that fan is there to operate after you shut down the engine. After shutdown, the engine block residual heat can raise coolant temps considerably. This 'auxiliary' fan could run after shutdown to keep the coolant from boiling or puking out coolant on the ground. It was likely the "precursor" to fully electric fans which can operate the same way.
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
For some reason I have always thought it was part of the RPO ZN1 Trailer Package (1,001 units in 1979). But...I really do not know.
7T1,
Note from the pic that the fan is powered when ignition is in the RUN position.
7T1,
Note from the pic that the fan is powered when ignition is in the RUN position.
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Le Mans Master
Joined: Feb 2011
Posts: 5,943
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From: Southern NH
i have the fan on my'81. does it pull enough CFM to work by itself without the belt driven fan, if a lower temp thermo switch was installed? what about a lower temp thermo switch and a larger aftermarket fan? it would be nice to make use of the factory wiring to get rid of the belt driven fan
Team Owner
Joined: Aug 1999
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From: Ontario
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Joined: Dec 2006
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From: Bisbee Arizona
Has to be a worst-case backup, what with its presence on on the "hi-po" L82 with a/c. Paul 74, thanx for the manual page print-out, I was able to locate it in my manual, missed it first time around.
Safety Car
Joined: Mar 2007
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From: Bridgewater nj
I unplugged the wires from the temp switch and installed a toggle switch under the dash. Worked great on hot days in traffic with the a/c on
Waiting for the engine to hit 238* is a little too late IMO
Waiting for the engine to hit 238* is a little too late IMO
Drifting
Joined: Jul 2007
Posts: 1,889
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From: Kansas
Yes Sir; The Auxiliary cooling fan is used for the purpose of cooling down the engine when in slow traffic & overheating might happen. It is powered through the Circuit breaker in the fuse panel when the ignition switch is in the run position. The fan motor is controlled by an engine temperature switch which screws into the engine block. When the engine temp. reaches approximately 238 degree F, the switch closes, completing the fan motor circuit to ground. The motor frame is its ground terminal and is insulated from engine ground by the plastic shroud surrounding it. When engine temp. decreases to approx. 201 F. the switch opens the fan circuit, shutting the fan off. Gene
