Fan shroud problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Solver · 11-22-2006, 09:51 PM

Got my engine back in and got her almost ready to fire up (just the plug wires fluids,tranny kickdown cable left).
Got the fan and shroud on tonight and just as I was finishing up I spun the fan and the darn thing hits the shroud on the driver side. I took pics and it looks like it's lined up properly. I am pretty sure it was for a 3 core or smaller cause I had to shim it out to fit radiator properly but the problem is the offset doesn't seem right! I have about 1 1/2- 2" clearance on passenger side and rubs on driver. Only thing I can think of is maybe the fan shroud is for a 4 wheel drive. Does the shroud offset that much more with a 4 wheel drive or is there something I am missing here? The spacing on the upper raiator mounts lines up pretty close so it bolts on right --just that darn offset

**Boog** · 11-22-2006, 10:03 PM

Is the radiator core support centered between the frame rails? I can't tell whether you have your fenders on or not either. If the support is sitting too far to the passenger side the blades could rub the shroud. Engine looks to be centered. Tranny crossmember all bolted up?

al's71gmc · 11-22-2006, 10:08 PM

This is probably a stupid question, but is the shroud upside down?

byrd · 11-22-2006, 10:10 PM

Al maybe on to something, it does look funny.

**Boog** · 11-22-2006, 10:22 PM

The mounting holes are spaced different between the top two and the bottom two so it couldn't mount upside down.

sameyrasmea72 · 11-22-2006, 10:40 PM

My very first 67-72 that I bought in 1991 was “missing “ the fan shroud. When it started having over heating problems, I went to add a shroud and had the same problem. After hours of frustration I finally realized the frame was slightly bent and caused the offset. This lead to a frame change and a two year restoration and I think to 15 year hobby with these trucks.

I am sure this is not the problem you’re having but I thought it was worth mentioning

Green Machine · 11-22-2006, 11:21 PM

Wow, all of our trucks are closer on the passenger side, not driver side. Try measuring from the crank center bolt to the frame. On our 68, I loosened up the frame to engine mount bolts and put a bottle jack between the frame and the balancer (no I don't think I bent the crank) to get it more centered. I could get some measurements if it would help.

Green Machine · 11-22-2006, 11:40 PM

Here's a couple quick measurements off of the 70. Inside of fender flat part to shroud center round part outer edge is exactly 24 inches both sides (tape at a slant), outside edges diameter is 19 1/2.

Solver · 11-23-2006, 12:28 AM

Thanks for the input guys.
Tom I went out and measured and the engine seems to be in Straight.
I did measure the fan shroud and that is where the difference is
The driver side of the fan shroud is closer to the center line by about 1 1/2"
from outside edge of shroud to round opening is 6" while the outside pass side to beginning of opening is only about 4 1/2 ". For some reason the fan shroud is offset . Must be for some other vehicle or designed to run with really short fan blades. In fact the first fan setup I had on there really didn't even clear the opening all the way around. Guess I'll try running without till next chance at the junkyard. Truck still needs the box done anyway

qksilver · 11-23-2006, 12:19 AM

Motor mounts?

corn · 11-23-2006, 01:59 AM

I went out & checked out the stocker on my 396 that Im sure isnt exactly the same but its all factory for the truck. I measured the centerline of the engine in the shroud & the centerline of the shroud itself. I do have to add that the top of yours looks a lot like the bottom of mine but it doesnt look like you can flip them over. A good way to tell is there is an indentation in the shroud for the petcock. The green in the pic is the shroud centerline & the red is the engine centerline. I also measured to the inner edge of the fenders to the outer edge of the radiator mounts. Hope it might help you a little...

I kind of messed up the pic a bit, the centerline measurments are to the inside of the mounts. In the pic they go to the outside. The only ones that I measured to the outside are to the fenders...

Blue85 · 11-23-2006, 02:12 AM

Wouldn't be for a 6cyl would it? someone once told me they sit a little over to the passenger side.

corn · 11-23-2006, 02:25 AM

My shroud radiator & engine all came in my truck & its not centered...

**Boog** · 11-23-2006, 07:53 AM

Solver, does it have the fenders on it and have you had the hood on it? Reason I ask is the front end has to be square in order for the hood to fit right. If the core support is too far to one side or the other the fan can make contact with the shroud. There is room at the core support to frame mounts to move it right or left an inch to inch and half. If the front sheet metal all lines up right then the radiator will be properly positioned in front of the engine, so should the shroud. I don't know the history of your build but is it possible the frame horns are both bent to the right?

PanelDeland · 11-23-2006, 12:36 PM

Blue 85,I have never seen more than just a mini/guard shroud on a 6 unless it was aftermarket.Did they make more of a shroud?
I would guess that being off center would mean either the frame/core support/engine mounts/or shroud is either the wrong one or out of adjustment.It may also be a combination of all those factors adding up to that much difference.

corn · 11-23-2006, 01:11 PM

Id almost put money on this. Go out measure yours (everyone), Ill bet its not centered. Anyone? Im interested in finding this out myself...

Solver · 11-23-2006, 11:17 PM

Thanks everyone for the input and Corn for the pic. I do have everything installed but the hood. Engine in V8 (front holes) and all the bolts went in on the frame stands without even pushing or pulling on the engine. Tranny mount was alittle skewed and thought maybe I had it in backwards but measured that today and the tranny mount holes are centered so even if I had the front of the tranny crossmember pointing backwards it shouldn't affect. I checked pics on internet last night and it seems all the shroud pics I found kind of showed an offset in the shroud hole location 4" one side 6" on other. I decided it was to much to think about so this morning I just swapped in a bigblock shroud I had tucked away as I have more of them than small block shrouds anway. Worked Fine!!!
So for now till hood goes on and I find out if I am skewed --Progress
Thanks for all the ideas to check for!!

11-22-2006, 09:51 PM	#1
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Fan shroud problems Got my engine back in and got her almost ready to fire up (just the plug wires fluids,tranny kickdown cable left). Got the fan and shroud on tonight and just as I was finishing up I spun the fan and the darn thing hits the shroud on the driver side. I took pics and it looks like it's lined up properly. I am pretty sure it was for a 3 core or smaller cause I had to shim it out to fit radiator properly but the problem is the offset doesn't seem right! I have about 1 1/2- 2" clearance on passenger side and rubs on driver. Only thing I can think of is maybe the fan shroud is for a 4 wheel drive. Does the shroud offset that much more with a 4 wheel drive or is there something I am missing here? The spacing on the upper raiator mounts lines up pretty close so it bolts on right --just that darn offset Attached Images __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

11-22-2006, 10:03 PM	#2
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: Fan shroud problems Is the radiator core support centered between the frame rails? I can't tell whether you have your fenders on or not either. If the support is sitting too far to the passenger side the blades could rub the shroud. Engine looks to be centered. Tranny crossmember all bolted up? __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

11-22-2006, 10:08 PM	#3
al's71gmc 4 eyed fever Join Date: Jul 2005 Location: Eureka, Nevada Posts: 500	Re: Fan shroud problems This is probably a stupid question, but is the shroud upside down? __________________ 1971 GMC 2500 4x4 1972 GMC Sierra Grande 1/2 t 4x4-#1 son's truck. Recently completed resto. 4 YO daughter," Daddy, I like your truck better than Mom's." (2000 F350-ranch truck) Smart kid!!

11-22-2006, 10:22 PM	#5
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: Fan shroud problems The mounting holes are spaced different between the top two and the bottom two so it couldn't mount upside down. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

11-22-2006, 10:40 PM	#6
sameyrasmea72 Senior Member Join Date: Aug 2003 Location: Lubbock, Texas Posts: 2,443	Re: Fan shroud problems My very first 67-72 that I bought in 1991 was “missing “ the fan shroud. When it started having over heating problems, I went to add a shroud and had the same problem. After hours of frustration I finally realized the frame was slightly bent and caused the offset. This lead to a frame change and a two year restoration and I think to 15 year hobby with these trucks. I am sure this is not the problem you’re having but I thought it was worth mentioning __________________ 72 Cheyenne Super 80 Silverado Blazer 2wd

11-22-2006, 11:21 PM	#7
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: Fan shroud problems Wow, all of our trucks are closer on the passenger side, not driver side. Try measuring from the crank center bolt to the frame. On our 68, I loosened up the frame to engine mount bolts and put a bottle jack between the frame and the balancer (no I don't think I bent the crank) to get it more centered. I could get some measurements if it would help. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0 Last edited by Green Machine; 11-22-2006 at 11:28 PM.

11-22-2006, 11:40 PM	#8
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: Fan shroud problems Here's a couple quick measurements off of the 70. Inside of fender flat part to shroud center round part outer edge is exactly 24 inches both sides (tape at a slant), outside edges diameter is 19 1/2. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

11-23-2006, 12:28 AM	#9
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Re: Fan shroud problems Thanks for the input guys. Tom I went out and measured and the engine seems to be in Straight. I did measure the fan shroud and that is where the difference is The driver side of the fan shroud is closer to the center line by about 1 1/2" from outside edge of shroud to round opening is 6" while the outside pass side to beginning of opening is only about 4 1/2 ". For some reason the fan shroud is offset . Must be for some other vehicle or designed to run with really short fan blades. In fact the first fan setup I had on there really didn't even clear the opening all the way around. Guess I'll try running without till next chance at the junkyard. Truck still needs the box done anyway Attached Images __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

11-23-2006, 12:19 AM	#10
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: Fan shroud problems Motor mounts?

11-23-2006, 01:59 AM	#11
corn Registered User Join Date: Dec 2003 Location: here Posts: 5,789	Re: Fan shroud problems I went out & checked out the stocker on my 396 that Im sure isnt exactly the same but its all factory for the truck. I measured the centerline of the engine in the shroud & the centerline of the shroud itself. I do have to add that the top of yours looks a lot like the bottom of mine but it doesnt look like you can flip them over. A good way to tell is there is an indentation in the shroud for the petcock. The green in the pic is the shroud centerline & the red is the engine centerline. I also measured to the inner edge of the fenders to the outer edge of the radiator mounts. Hope it might help you a little... I kind of messed up the pic a bit, the centerline measurments are to the inside of the mounts. In the pic they go to the outside. The only ones that I measured to the outside are to the fenders... Last edited by corn; 10-04-2007 at 06:36 PM.

11-23-2006, 02:12 AM	#12
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,170	Re: Fan shroud problems Wouldn't be for a 6cyl would it? someone once told me they sit a little over to the passenger side. __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

11-23-2006, 02:25 AM	#13
corn Registered User Join Date: Dec 2003 Location: here Posts: 5,789	Re: Fan shroud problems My shroud radiator & engine all came in my truck & its not centered...

11-23-2006, 07:53 AM	#14
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: Fan shroud problems Solver, does it have the fenders on it and have you had the hood on it? Reason I ask is the front end has to be square in order for the hood to fit right. If the core support is too far to one side or the other the fan can make contact with the shroud. There is room at the core support to frame mounts to move it right or left an inch to inch and half. If the front sheet metal all lines up right then the radiator will be properly positioned in front of the engine, so should the shroud. I don't know the history of your build but is it possible the frame horns are both bent to the right? __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

11-23-2006, 12:36 PM	#15
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Fan shroud problems Blue 85,I have never seen more than just a mini/guard shroud on a 6 unless it was aftermarket.Did they make more of a shroud? I would guess that being off center would mean either the frame/core support/engine mounts/or shroud is either the wrong one or out of adjustment.It may also be a combination of all those factors adding up to that much difference. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

11-23-2006, 01:11 PM	#16
corn Registered User Join Date: Dec 2003 Location: here Posts: 5,789	Re: Fan shroud problems Id almost put money on this. Go out measure yours (everyone), Ill bet its not centered. Anyone? Im interested in finding this out myself...



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11-23-2006, 11:17 PM	#17
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Re: Fan shroud problems Thanks everyone for the input and Corn for the pic. I do have everything installed but the hood. Engine in V8 (front holes) and all the bolts went in on the frame stands without even pushing or pulling on the engine. Tranny mount was alittle skewed and thought maybe I had it in backwards but measured that today and the tranny mount holes are centered so even if I had the front of the tranny crossmember pointing backwards it shouldn't affect. I checked pics on internet last night and it seems all the shroud pics I found kind of showed an offset in the shroud hole location 4" one side 6" on other. I decided it was to much to think about so this morning I just swapped in a bigblock shroud I had tucked away as I have more of them than small block shrouds anway. Worked Fine!!! So for now till hood goes on and I find out if I am skewed --Progress Thanks for all the ideas to check for!! Attached Images __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

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