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Old 10-07-2012, 01:56 PM   #1
crx686
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Fan Shroud

Hi

My name is Ben I have A GMC 1969 1/2 ton p/u truck.....I bought this truck and it didnt have a fan shroud. So I buy a fan shroud from LMC trucks it bolts on just fine but the fan is not center in the shroud so the right side of the fan hits the shroud making noise while it runs... I really don't want to modify it..suppose to be OE replacement...It had a spacer on the fan.. so i changed it back to a clutch fan thinking it would push the fan out more...it didn't..I dont understand why its not center... anyone have any ideas? Thanks
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Old 10-07-2012, 02:02 PM   #2
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Re: Fan Shroud

Welcome to the forum from the Temecula area.

Hit up forum member "jeremiah king" and his wife Jen, they live in Julian as well and are very nice people that scrounge and sell parts for 67-72 trucks.
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Old 10-07-2012, 02:17 PM   #3
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Re: Fan Shroud

Welcome from NorCal. If you can locate another shroud and they measure out the same, maybe there's a problem with the motor mounts -- broken and/or worn out, or wrong mount(s) entirely.... Good luck, I hope you get it figured out, and post the results here.
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Old 10-07-2012, 03:36 PM   #4
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Re: Fan Shroud

welcome to the board from Texas, you might see if the size of you fan can be changed, i know some are bigger than others, might check other year models , for size, also check with lmc and make sure you have the right shroud ...
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Old 10-07-2012, 03:42 PM   #5
GASoline71
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Re: Fan Shroud

Most of the OEM replacemnt shrouds don't fit well at all. It's why I waited to finally find an Origianl GM shroud for my truck. I got it used from Wes at "Classic Heartbeat" a forum sponsor/vendor.

Also your radiator support bushings on the frame and the radiator mounts themselves could be rotten, and throwing the front end out of whack.

Gary
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My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread.

The Rebuild of Creeping Death after the wreck

Quote:
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I would never rebuild a 305.
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I love using vacuum gauges as part of the carb tuning process. I hook the gauge to the inside of my garbage can and leave it there.
Quote:
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Remember Murphys 2nd law of mechanical relationships... "OPPOSING COMPONENTS ATTEMPTING TO OCCUPY THE SAME SPACE, AT THE SAME TIME, GENERALLY END UP OCCUPYING ADJOINING SPACE AT THE BOTTOM OF THE OIL PAN"
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Old 10-07-2012, 04:23 PM   #6
crx686
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Re: Fan Shroud

I know them... I looked at the mounts and there metal i dont know how they can be worn. I know there the right mounts...All the trucks i've seen in the junk yard and my friends have the same mounts....
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Old 10-07-2012, 04:32 PM   #7
GASoline71
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Re: Fan Shroud

The radiator support mounts that are between the support and the frame could be worn out. Common on these old trucks.

Also the radiator mounts have rubber "cups" in them, so the radiator will not rub the metal. Another common rubber part that wears out.

Gary
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My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread.

The Rebuild of Creeping Death after the wreck

Quote:
Originally Posted by LONGHAIR View Post
I would never rebuild a 305.
Quote:
Originally Posted by prostreetC-10 View Post
I love using vacuum gauges as part of the carb tuning process. I hook the gauge to the inside of my garbage can and leave it there.
Quote:
Originally Posted by Marv D View Post
Remember Murphys 2nd law of mechanical relationships... "OPPOSING COMPONENTS ATTEMPTING TO OCCUPY THE SAME SPACE, AT THE SAME TIME, GENERALLY END UP OCCUPYING ADJOINING SPACE AT THE BOTTOM OF THE OIL PAN"
Quote:
Originally Posted by cableguy0 View Post
Its cheaper to listen to advice given when you ask for help than it is to ignore everyone and wait for carnage.
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Old 10-07-2012, 04:39 PM   #8
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Re: Fan Shroud

the rad. has to have rubber bushing in the metal mounts...if they are missing , than go get some rubber.....it has to have them....
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Old 10-07-2012, 04:45 PM   #9
crx686
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Re: Fan Shroud

I'll get new mounts for it.. I have a hard time understanding that its it.. the rubber part is whats in the mount holding the radiator... But the whole mount is metal which is what the shroud is hooked up to... and attached to the frame....but i'll raplace it...maybe i'm not seeing it.. Thanks for the help.....
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Old 10-07-2012, 05:01 PM   #10
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Re: Fan Shroud

Again... if the radiator cups are worn and completely gone... the radiator will sit wonky in the bay, causing the shroud to sit wonky as well, and rub the fan. Same for the mounts under the rad support near the frame. When they are worn out. The entire front of the truck sits wonky over the frame, and can cause the fan to rub the shroud.

Clear as mud?

Gary
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'cuz chicks dig scars...

My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread.

The Rebuild of Creeping Death after the wreck

Quote:
Originally Posted by LONGHAIR View Post
I would never rebuild a 305.
Quote:
Originally Posted by prostreetC-10 View Post
I love using vacuum gauges as part of the carb tuning process. I hook the gauge to the inside of my garbage can and leave it there.
Quote:
Originally Posted by Marv D View Post
Remember Murphys 2nd law of mechanical relationships... "OPPOSING COMPONENTS ATTEMPTING TO OCCUPY THE SAME SPACE, AT THE SAME TIME, GENERALLY END UP OCCUPYING ADJOINING SPACE AT THE BOTTOM OF THE OIL PAN"
Quote:
Originally Posted by cableguy0 View Post
Its cheaper to listen to advice given when you ask for help than it is to ignore everyone and wait for carnage.
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Old 10-07-2012, 05:01 PM   #11
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Re: Fan Shroud

Does the fan hit while it is idleing or when you throttle it?
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Old 10-07-2012, 05:25 PM   #12
crx686
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Re: Fan Shroud

Yes clear as rain...ill put new mounts on it....the fan hits when the engine turns....
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Old 10-07-2012, 05:33 PM   #13
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Re: Fan Shroud

what size is the fan, i have 18" fans on all mine and a 17" on my wifes, tried a 19" once and it hit the shroud, i got my shroud from the truck shop and it worked fine the rest are all oe shrouds, good oe shrouds are hard to find, hope your able to get it working
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Old 10-07-2012, 05:54 PM   #14
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Re: Fan Shroud

I agree with the rubber bushings being worn. I bought an LMC shroud and mounted with no problem or rubbing. Actually, I have never had a problem anything I have order thru them.

Hope that new bushings solve your problem.
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Old 10-07-2012, 06:47 PM   #15
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Re: Fan Shroud

Quote:
Originally Posted by GASoline71 View Post
Again... if the radiator cups are worn and completely gone... the radiator will sit wonky in the bay, causing the shroud to sit wonky as well, and rub the fan.
Doesn't the top of the shroud bolt directly to the iron brackets that bolt directly to the core support with no rubber in between?
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Old 10-07-2012, 07:13 PM   #16
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Re: Fan Shroud

Well I'd suspect the drivers side motor mount first.
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Old 10-07-2012, 07:29 PM   #17
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Re: Fan Shroud

Before you start messing with motor mounts, check two things:
1. Be sure you have the right fan shroud. There is a difference between big block and small block shrouds.
2. Be sure your hoods and fenders are on straight.

I had exactly the same problem. The PO gave me a fan shroud when I bought the truck. Since we live less than 10 minutes from LMC, I presume that's where it came from. If you stand at the front of my ride and look at it straight on, you could see that the gaps between the hood and fenders were not even. On one side the gap was wider near the grill than at the cowl. The other side was just the opposite.

This means that the front end was not on straight. I confirmed this by measuring diagonally under the hood. Find a spot near the cowl and the core support that is the same on both sides and measure diagonally. If the measurements are not the same, you need to move the whole front end one way or the other.

The easiest way to do this is to loosen the fenders where they attach to the cowl and loosen the core support where it bolts to the frame under the radiator. Then you can move it right or left (you may need a porta-power or jack). Once everything lines up, tighten things back up and you should be good.
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Old 10-08-2012, 12:05 AM   #18
haminator
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Re: Fan Shroud

Quote:
Originally Posted by kcsa75 View Post
Before you start messing with motor mounts, check two things:
1. Be sure you have the right fan shroud. There is a difference between big block and small block shrouds.
2. Be sure your hoods and fenders are on straight.

I had exactly the same problem. The PO gave me a fan shroud when I bought the truck. Since we live less than 10 minutes from LMC, I presume that's where it came from. If you stand at the front of my ride and look at it straight on, you could see that the gaps between the hood and fenders were not even. On one side the gap was wider near the grill than at the cowl. The other side was just the opposite.

This means that the front end was not on straight. I confirmed this by measuring diagonally under the hood. Find a spot near the cowl and the core support that is the same on both sides and measure diagonally. If the measurements are not the same, you need to move the whole front end one way or the other.

The easiest way to do this is to loosen the fenders where they attach to the cowl and loosen the core support where it bolts to the frame under the radiator. Then you can move it right or left (you may need a porta-power or jack). Once everything lines up, tighten things back up and you should be good.
Good call.
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Old 10-08-2012, 09:50 AM   #19
GASoline71
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Re: Fan Shroud

Quote:
Originally Posted by 1972RedNeck View Post
Doesn't the top of the shroud bolt directly to the iron brackets that bolt directly to the core support with no rubber in between?
Yep, good call. I FUBAR'd that one.

So to the OP... with that being said. I'd check those core support bushings, and check the front end as kcsa75 said.

Gary
__________________
'cuz chicks dig scars...

My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread.

The Rebuild of Creeping Death after the wreck

Quote:
Originally Posted by LONGHAIR View Post
I would never rebuild a 305.
Quote:
Originally Posted by prostreetC-10 View Post
I love using vacuum gauges as part of the carb tuning process. I hook the gauge to the inside of my garbage can and leave it there.
Quote:
Originally Posted by Marv D View Post
Remember Murphys 2nd law of mechanical relationships... "OPPOSING COMPONENTS ATTEMPTING TO OCCUPY THE SAME SPACE, AT THE SAME TIME, GENERALLY END UP OCCUPYING ADJOINING SPACE AT THE BOTTOM OF THE OIL PAN"
Quote:
Originally Posted by cableguy0 View Post
Its cheaper to listen to advice given when you ask for help than it is to ignore everyone and wait for carnage.
GASoline71 is offline   Reply With Quote
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