Author Topic: 1976 C20 fan shroud  (Read 3254 times)

Offline Henry

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1976 C20 fan shroud
« on: July 29, 2017, 12:50:37 PM »
Hi:
Can anyone tell me or show me what the correct fan shroud should be for my 1976 C20 truck? It is a C20, 2WD, has A/C, 350 motor, T400 tranny. From some parts supplier catalogs, it seems that my truck should have a 2-piece shroud...mine has a one piece shroud (GM p/n 6264137) and it does not fit very well (clips at bottom  barely engage). The fan also has a spacer that does not look original GM. I am trying to get my truck to original configuration and have everything fit properly. I understand 1976/77 were transition years for the squarebody and that I may have parts that are not common. Any help would be appreciated.
Regards,
Henry

Offline VileZambonie

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Re: 1976 C20 fan shroud
« Reply #1 on: July 29, 2017, 03:40:48 PM »
You should have the one piece shroud but pix would help. What upper radiator support do you have? that will determine which shroud will fit correctly.
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Offline Henry

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Re: 1976 C20 fan shroud
« Reply #2 on: July 31, 2017, 12:38:30 PM »
Hi Vile:
I have 3 photos of the shroud, upper support, and radiator fit. Each image is 750kB and too large to attach to this message...can I send them to your e-mail? The fan shroud has a depth of 6 inches. The upper radiator support has a width of 31 inches and a depth of 3.5 inches. When I temporarily assembled the radiator and upper support for a pic, I noticed that it is a real tight fit...maybe I have the wrong radiator in this truck and it is causing the upper radiator support to jack up as you see in the pic and causing the fan shroud to mount too high for the lower clips to engage. The radiator core size is 16.25 inch ht, 28.25 inch wd, and 2.75 inch depth, and 4-rows. What do you think?
Regards,
Henry

Offline VileZambonie

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Re: 1976 C20 fan shroud
« Reply #3 on: August 01, 2017, 11:41:34 AM »
These are the pics you sent me.
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Offline VileZambonie

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Re: 1976 C20 fan shroud
« Reply #4 on: August 01, 2017, 11:43:42 AM »
It appears you have the correct shroud for your setup. The larger radiator has a flat upper panel support and the top of the shroud is level with the opening. So basically you have the junior setup and it probably isn't seated correctly at that bottom.
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Offline Henry

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Re: 1976 C20 fan shroud
« Reply #5 on: August 01, 2017, 12:12:58 PM »
Hi Vile:
As you can see from the "fit" photo, once the rubber isolators are snapped into place on both the top and bottom radiator supports, I really have to press the whole assembly down and to the front to get the upper support screws to line up and tighten  down. As you can see, the rear lip of the upper support barely goes over the top of the radiator. I know I replaced this radiator decades ago and I suspect that I may have "upgraded" from 2 or 3-row and that it is too thick for the upper support. I guess I will try to see if the stock radiator is supposed to be a little thinner, and if I cannot find out maybe the solution is to cut some rubber off those isolators to let the radiator sit a bit lower and forward so maybe the lower clips can engage better. What is meant by the "junior setup"?
Regards,
Henry

Offline VileZambonie

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Re: 1976 C20 fan shroud
« Reply #6 on: August 01, 2017, 01:54:59 PM »
It means you do not have the heavy duty cooling system setup. The taller radiator, shroud and flat panel upper support.

Try installing it with only the top of the shroud connected and then look to see where it lands near the bottom. If it looks close then the radiator is probably out of position.
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Offline Henry

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Re: 1976 C20 fan shroud
« Reply #7 on: August 02, 2017, 07:38:09 AM »
Hi Vile:
When I installed it for the photo, the radiator lined up very well with the snapped in rubber isolators: the isolators were right on the radiator side tank seam lines both directions...but it seems like the side tanks are too wide for the isolators. I will go ahead and do another fit check like you say without the isolators and see what position the shroud wants to be to get the lower clips fully engaged. I will let you know.

I was looking through the Classic Industries catalog and their 4-row radiator for my truck has the same core dimensions as mine: 17" x 28-3/8" x 2-5/8". Their 3-row radiator measures 17" x 28-3/8" x 2"...if their size info is correct, I am wondering if that 5/8" difference in the 3 vs 4-row thickness is what my fit problems is. I also see that they have two different sizes of isolators. I will call them and see what the isolator differences are.
Regards,
Henry

Offline Henry

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Re: 1976 C20 fan shroud
« Reply #8 on: August 09, 2017, 03:08:45 PM »
Hi Vile:
So I purchased some new isolators that have an overall length of 4.25 inch and a 3.5 inch internal groove that is a perfect fit for my 4-row radiator that has a tank width of 3.5 inches. These isolators also fit my upper and lower radiator supports perfectly. My previous isolators had a 3.75 inch overall length and a 2.75 inch internal groove and were somewhat distorted and caused the tight fit of my upper radiator support. So these new isolators fit the tanks of the 4-row radiator perfectly but the upper isolator needed to be bent a bit for the installation of the upper support to fit properly...one this was done, the radiator installed easily and appeared to be a nice fit. The radiator shroud then was installed and the upper screws attached to the upper support with no problem. The original problem was still there though: the lower clips for the shroud were vertically in line, but the shroud was .5 inch too far to the rear to engage the clips. No amount of bending the shroud would allow engagement. I believe the problem to be that my truck originally had a 3-row radiator which my local radiator shop says had 2.75 inch wide tanks. This is a .75 inch reduction in the width of the tank which would solve my .50 inch shroud fit problem. So I have concluded that my solution to this problem is to get a standard Chevy truck 3-row radiator or make a modification at the lower clip mount of the shroud to allow the 4-row radiator to fit. I do think you are right  that my one piece shroud is the correct shroud for my truck and that the standard radiator that came in my C20 was probably a 3-row. I think a 4-row probably was an option or for the 454 engine...my build sheet does not indicate a radiator option was installed.
Regards,
Henry

Offline VileZambonie

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Re: 1976 C20 fan shroud
« Reply #9 on: August 09, 2017, 09:05:21 PM »
Basically you have the wrong radiator crammed in there
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Offline Henry

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Re: 1976 C20 fan shroud
« Reply #10 on: August 10, 2017, 09:44:15 AM »
Yup...thanks for the help.
Regards,
Henry