Lower fan shroud and core support mounts????? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**71CHEVYSHORTBED402** · 05-10-2015, 12:57 AM

71 Chevy 402:

I was told long ago my fan shroud is the wrong one. Well, after getting a new one it's confirmed what's on the truck is original. No harm done, there are 3-4 cut outs on the existing shroud all but one completely unnecessary, more on that in a moment. Shame too, because the top is beautiful. Also a crack in an ear. The new one is real nice.

At any rate, the shroud on the truck doesn't seem to want to reach the bottom clips. I would imagine they should go all the way in, but these don't come close. Is this because the core support mounts are bad? I'm replacing them regardless. Suddenly it makes sense why so many of these shrouds are hit by the fan. Mine is held down with two zip ties. Been good for decades. Possible just a poor design? Seems to me four bolts are better than two.

One of the cutouts on the existing shroud is for the hose line from the heater core to near the top of the radiator. Seems the hose connection and shroud are a tight squeeze, after all, someone cut the existing shroud for it (bastads). That said, the shroud tends to want to "form" into that direction (i.e., not straight up and down). May also be the core support mounts? Possibly the wrong radiator? The radiator is approx. 34 1/8" wide. Has anyone else experienced this and what did you do? Update: Must be the radiator is incorrect or the inlet welded to the radiator for the heater core in doesn't suit the original shroud.

**71CHEVYSHORTBED402** · 05-10-2015, 02:37 AM

I suspect I need a wider radiator. That or the heater core in outlet on the radiator closer to the passenger side. Any big block owners have a suggestion for a radiator?

**71CHEVYSHORTBED402** · 05-12-2015, 02:27 PM

Quote:

Originally Posted by 71CHEVYSHORTBED402

71 Chevy 402:

The stock shroud on the truck doesn't seem to want to reach the bottom clips. I would imagine they should go all the way in, but these don't come close. Is this because the core support mounts are bad? I'm replacing them regardless. Suddenly it makes sense why so many of these shrouds are hit by the fan. Mine is held down with two zip ties. Been good for decades. Possible just a poor design? Seems to me four bolts are better than two.

Any big block owners experience this? What was the cause?

**71CHEVYSHORTBED402** · 05-12-2015, 11:11 PM

?...........I'm sure I can figure it out once I dive in, but doesn't mean I'm not curious. Shroud shrinkage? Ha!

**kwmech** · 05-12-2015, 11:14 PM

I've got 3 trucks set up for big block, 2 with actual big blocks in them. Got a picture of the shroud and the issue?

**71CHEVYSHORTBED402** · 05-13-2015, 01:12 PM

Quote:

Originally Posted by kwmech

I've got 3 trucks set up for big block, 2 with actual big blocks in them. Got a picture of the shroud and the issue?

I can take a picture if necessary, but it's not going to tell more than words I think. Here's the deal:

The fan shroud on my truck is original (3924932). These shrouds are mounted to the core support with two bolts and retainers at the top, and two clips at the bottom (see picture below for the clips)

Unless the core support or top retainers are incorrect, the top is straight forward. The problem is, with the shroud mounted to the top, the bottom of the shroud doesn't reach to insert into the bottom clips. One side reaches the top of one clip, the other doesn't even do that. Whatever the issue is, I believe this is why so many of these shrouds have been damaged by a fan.

If you ask me, keeping in mind I'm green and haven't dove into the front end yet, seems like a poor GM design. I'd think four bolts are better than two bolts and two clips. Again, this may be that the core support mounts are bad.

sduckworth13 · 05-13-2015, 01:24 PM

I had the same issue. I went to the hardware store and bought some small bushings with a hole for the bolt to fill the void area and bolted the radiator shroud down using the holes in the shroud.

**71CHEVYSHORTBED402** · 05-13-2015, 01:34 PM

Quote:

Originally Posted by sduckworth13

I had the same issue. I went to the hardware store and bought some small bushings with a hole for the bolt to fill the void area and bolted the radiator shroud down using the holes in the shroud.

That's the other thing, why do these shrouds have a bolt hole at each corner when as I understand it, they don't even bolt at the bottom? Seems I'm missing a piece of the puzzle.

**leddzepp** · 05-13-2015, 01:41 PM

I'll bet your core support mounts are shot.

67chevemall · 05-13-2015, 01:46 PM

Maybe GM was going to bolt it until they realized the shrinkage issue and had the clips made up quick

**71CHEVYSHORTBED402** · 05-13-2015, 01:51 PM

Quote:

Originally Posted by leddzepp

I'll bet your core support mounts are shot.

Could be the issue. No doubt I need new mounts. Just not sure that's what causes the problem.

sduckworth13 · 05-13-2015, 01:59 PM

I'm pretty sure there were holes in my core support that lined up with the bottom hole in my shroud. I thought I was going to crack the shroud to close the gap up on the bottom. It worked out pretty nice.

**71CHEVYSHORTBED402** · 05-13-2015, 02:15 PM

Quote:

Originally Posted by sduckworth13

I'm pretty sure there were holes in my core support that lined up with the bottom hole in my shroud. I thought I was going to crack the shroud to close the gap up on the bottom. It worked out pretty nice.

Guess I'll see what you mean during the rebuild. Sounds like you're not using the bottom clips. Note: Also sounds like it could be your core mounts are bad. Don't really know much about it at this point.

sduckworth13 · 05-13-2015, 11:05 PM

Here are some pictured of my lower shroud setup.

**71CHEVYSHORTBED402** · 05-14-2015, 12:02 AM

Quote:

Originally Posted by sduckworth13

Here are some pictured of my lower shroud setup.

Interesting. Looks like it works. Unusual how the shrouds have a hole in each corner, yet the lowers "are supposed to" just seat into the clips. Then as you've shown, the holes on the core line up. Possible the cores were leftover stock from former years where they did bolt up. If true, why the change? It's a dog gone mystery.

Just a thought and you may not like it. If the shrouds no longer reach to properly mount into the clips, because the core support mounts are bad, then if your mounts fail your shroud will be damaged. Something has to give.

sduckworth13 · 05-14-2015, 12:24 AM

Quote:

Originally Posted by 71CHEVYSHORTBED402

Interesting. Looks like it works. Unusual how the shrouds have a hole in each corner, yet the lowers "are supposed to" just seat into the clips. Then as you've shown, the holes on the core line up. Possible the cores were leftover stock from former years where they did bolt up. If true, why the change? It's a dog gone mystery.

Just a thought and you won't like it. If the shrouds no longer reach to properly mount into the clips, because the core support mounts are bad, then that doesn't bode well for your shroud dude. Something has to give.

I'm sure the mounts are probably disintegrated.

**71CHEVYSHORTBED402** · 05-14-2015, 12:57 AM

Quote:

Originally Posted by sduckworth13

I'm sure the mounts are probably disintegrated.

LOL...........Probably so. WTH do I know anyway.

05-10-2015, 12:57 AM	#1
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,129	Lower fan shroud and core support mounts????? 71 Chevy 402: I was told long ago my fan shroud is the wrong one. Well, after getting a new one it's confirmed what's on the truck is original. No harm done, there are 3-4 cut outs on the existing shroud all but one completely unnecessary, more on that in a moment. Shame too, because the top is beautiful. Also a crack in an ear. The new one is real nice. At any rate, the shroud on the truck doesn't seem to want to reach the bottom clips. I would imagine they should go all the way in, but these don't come close. Is this because the core support mounts are bad? I'm replacing them regardless. Suddenly it makes sense why so many of these shrouds are hit by the fan. Mine is held down with two zip ties. Been good for decades. Possible just a poor design? Seems to me four bolts are better than two. One of the cutouts on the existing shroud is for the hose line from the heater core to near the top of the radiator. Seems the hose connection and shroud are a tight squeeze, after all, someone cut the existing shroud for it (bastads). That said, the shroud tends to want to "form" into that direction (i.e., not straight up and down). May also be the core support mounts? Possibly the wrong radiator? The radiator is approx. 34 1/8" wide. Has anyone else experienced this and what did you do? Update: Must be the radiator is incorrect or the inlet welded to the radiator for the heater core in doesn't suit the original shroud. __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s details such as OEM identifications& part numbers, written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025 Last edited by 71CHEVYSHORTBED402; 05-13-2015 at 01:54 PM.

05-10-2015, 02:37 AM	#2
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,129	Re: Lower fan shroud and core support mounts????? I suspect I need a wider radiator. That or the heater core in outlet on the radiator closer to the passenger side. Any big block owners have a suggestion for a radiator? __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s details such as OEM identifications& part numbers, written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025

05-12-2015, 11:11 PM	#4
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,129	Re: Lower fan shroud and core support mounts????? ?...........I'm sure I can figure it out once I dive in, but doesn't mean I'm not curious. Shroud shrinkage? Ha! __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s details such as OEM identifications& part numbers, written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025

05-12-2015, 11:14 PM	#5
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,398	Re: Lower fan shroud and core support mounts????? I've got 3 trucks set up for big block, 2 with actual big blocks in them. Got a picture of the shroud and the issue?

05-13-2015, 01:24 PM	#7
sduckworth13 Registered User Join Date: Mar 2011 Location: Kansas City, Missouri Posts: 3,541	Re: Lower fan shroud and core support mounts????? I had the same issue. I went to the hardware store and bought some small bushings with a hole for the bolt to fill the void area and bolted the radiator shroud down using the holes in the shroud. __________________ Scott

05-13-2015, 01:41 PM	#9
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,989	Re: Lower fan shroud and core support mounts????? I'll bet your core support mounts are shot. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man

05-13-2015, 01:46 PM	#10
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Re: Lower fan shroud and core support mounts????? Maybe GM was going to bolt it until they realized the shrinkage issue and had the clips made up quick __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

05-13-2015, 01:59 PM	#12
sduckworth13 Registered User Join Date: Mar 2011 Location: Kansas City, Missouri Posts: 3,541	Re: Lower fan shroud and core support mounts????? I'm pretty sure there were holes in my core support that lined up with the bottom hole in my shroud. I thought I was going to crack the shroud to close the gap up on the bottom. It worked out pretty nice. __________________ Scott

05-13-2015, 11:05 PM	#14
sduckworth13 Registered User Join Date: Mar 2011 Location: Kansas City, Missouri Posts: 3,541	Re: Lower fan shroud and core support mounts????? Here are some pictured of my lower shroud setup. Attached Images __________________ Scott



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