Electric fans

[VetteV8]

According to the documentation in the Chevrolet shop manual for our year, the '81 should have an auxiliary electric fan behind the radiator. [Ref page 6B8-6B9 ]

Mine has not, and there are no tell-tales it ever had it.
Now, mine it from september 81, so one of the last of this model year.
Is there chance that at some time the electric fans were discontinued for the '81 during the production cycle??

{my VIN ends on 107552 and the body tag decodes to Sept, 5th week, from Bowling Green}

thanks,
Cor

 

[Peer81]

Maybe if your vette didn't have airco then maybe.
But you can look between cylinder 5 and 7, if there is a sensor in the head, follow the leads, they are for the aux fan.

Greetings Peter

 

[VetteV8]

It does have an A/C Peter, and it's working too.
I'll have a look at the sender tomorrow; it shows in the manual on pic. 6B7
Thanks,
Cor

 

[GerryLP]

In my L81, the thermal switch is on the right side, between 6 and 8. That heat shield that goes rear/rh side has a hole from which the wires connect.

The wires for it are part of the starter extension harness.

 

[bill81vette]

Perhaps at some point in its life,it stopped working and some one pulled it out....

 

[VetteV8]

That's right Gerry!

There is a temp. sender with 2 prongs on the righthand side of the engine between the last 2 cylinders, as also shown in the shop manual.
But as I said earlier, there is no sign that an electric fan has ever been installed or subsequently been removed.

I have read previously, but can not find it back, that along with the electric fan, installation, the main fan has been reduced in size, for power and noise reasons.
I have measured mine, and the overall fan diameter is 57 cm, which equals 22.5"
There is an airgap at the top of about 1/2", more at the bottom and the sides. That is the gap between the fantips and the shroud.
Is all this normal for an '81?
Thanks,
Cor

 

[GerryLP]

Here is an easy view of its location.

 

[bill81vette]

If I remember (without looking)the fan was bolted to the inside of the shroud,plus the wiring harness for it goes down into the shroud as well...

 

[6880 Mike]

79 and 80 L-82 cars, and all 81-82s had the auxilary electric fans. L-82 cars had the trap door fan shrouds. 81-82 did not.

80 L-82 shown; 81-82 are similar.

 

[Tim81]

The connector for the fan motor is hidden under the air cleaner plastic ducting along the passinger side fender. I'm not sure of the wire coloring but the connector is a pretty good size two pin connector. I want to say one wire is green and one is white, not sure...

 

[Peer81]

It's not difficult to remove the thing and the wiring. On the other hand it's also not difficult to install it back again if you buy the parts.

btw. Gerry is right, I started counting cylinders at the wrong side..

Greetings Peter

 

[GerryLP]

79 and 80 L-82 cars, and all 81-82s had the auxilary electric fans. L-82 cars had the trap door fan shrouds. 81-82 did not.

80 L-82 shown; 81-82 are similar.

Very cool, Mike! I couldn't find a picture of mine.

The 81 bracing for the fan is configured differently, but it attaches similarly to the shroud.

Every day I learn something new. What was the trap door for and how or when is used?


GerryLP:cool

 

[VetteV8]

Thanks all, with all this info above, I have been able to put the 'picture' together.
A little bit of feedback is the least I can do!
Here it goes:I have found the mounting holes for the fan although these are not shown in Mike's pictures , but I used one of these to mark the holes which I found in my shroud

the detail of mounting #1 is shown here

And the detail of #2 here:

the 3rd position could not be photographed, but is located in a dimple in the shroud at #3. This dimple is not present in the pictures from Mike.

The electric connector is pretty obvious at the A/C compressor; I had noticed that before, but did not have any idea what it was for; it is indeed a beefy connetcotor laying along the A/C connector and wired up in the same loom as for the A/C clutch. The wires are Green and Black.

Next I will try to undo the thermoswitch connector and short this out, with the ignition ON, and see if I am getting any voltage on the fan connector..................

The engine fan has p/n 1402320.....916938 G81
It is a bit of a funny one, as the blades are not eaqually spaced: there are 3 wide spaced and 2 narrow; I guess this has something to do with noise or blade resonance??

For your info, the cut out, or trap door at the bottom of Mike's picture does not seem original and is not present on mine; I my view, it looks like this cut out has been made to remove the electric fan without having to remove anything else; pleased to see this has not been done on my car this way, where it has been removed in a decent way

Thanks again all!

Cor

 

[6880 Mike]

...The 81 bracing for the fan is configured differently, but it attaches similarly to the shroud...

Correct. 81 and 82 have flat legs on the fan mount. 79 and 80 have the round bars as shown.

I'm not sure of the whys and wherefores of the L-82 trap door. I've heard mine close in the past, but was never certain when it opened. Opening and closing is mechanical, possibly from air flow based on engine fan speed.

The trap door earns a second fan warning sticker placed on the underside of the shroud and visible from under the car when the car is on a lift.

VetteV8: 81 and 82s do not have the trap door. The setup and shroud in my pics are original L-82 pieces. Nothing has been cut. The 81 assembly instruction manual (AIM) will show how the auxilary fan was installed in your car and list the original GM part numbers. Complete units show up on eBay from time to time.

 

[GerryLP]

...
Next I will try to undo the thermoswitch connector and short this out, with the ignition ON, and see if I am getting any voltage on the fan connector..................

To short the thermoswitch, and if the right rear heat shield is not in place, you can simply place a wide-bladed common screw driver across the switch's connector blades, and read the voltage at the other end.

 

[GerryLP]

...
I'm not sure of the whys and wherefores of the L-82 trap door. I've heard mine close in the past, but was never certain when it opened. Opening and closing is mechanical, possibly from air flow based on engine fan speed.

The trap door earns a second fan warning sticker placed on the underside of the shroud and visible from under the car when the car is on a lift....

That's pretty cool, Mike. So I gather that the trap door, and perhaps this obvious to other folks, is spring-loaded shut?

I always worry the few times I am unable to dodge a plastic bag or piece of carton out in the freeway, for the possibility of that stuff blocking the grill area at the once of the Vette and causing overheating.

 

[6880 Mike]

...I gather that the trap door...is spring-loaded shut?...

No springs. It appears to balance on the two hinges. Regular position is shut.

 

[Tommy Almond]

Automatic to Manual Change???

Have any of you wired the electric fan to a switch you can control? I'm thinking if did this then could when car is stopped and engine off, to move air still in engine compartment the heat built up should be reduced thus reducing chance of boiling gas. Just install a manual toggle switch sorta item and flip on when needed if connected straight to always hot power source. Thoughts, comments?

 

[black_81_vette]

I hooked up a adjustable switch to my 81,you can get the switch at any parts store for around 25 bucks. I set mine to come on at 200 degrees but Its never got hot enough to ever turn it on since I went with a 180 t-stat. I figure its good to have it there if I need it. Btw all I did was wire the switch to the wiring that goes to the fan and eliminated the sender in the head.