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Weird rattle sound like something stuck in the fan???

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84hurst
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Weird rattle sound like something stuck in the fan???

Postby 84hurst on Thu Jul 01, 2010 12:54 am

Allright im gonna try to describe this the best i can. i have a stock 84 H/O with the 307 of course, I get this weird noise kind of like a sound when something's stuck in a fan and kind of flaping back and fourth, Its always there when you start it cold, but then if you get on it when its warmed up it goes away. WTF??? It still does it in park so i can eliminate anything from the trans back. It gets louder as the engine rpm's rise, its not the smog pump as the barrings went bad so i cut the belt. The fan shroud is as clean as can be. So im lost as to what else could be spinning and making this noise? Anybody have any ideas or heard this???
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othtim
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Re: Weird rattle sound like something stuck in the fan???

Postby othtim on Tue Oct 26, 2010 3:34 pm

I know this is an old thread. But all of a sudden, my car is making a sound that is very similar. I was actually searching through old posts looking for some help, but I stumbled across this thread which already accurately describes the issue I am having. Sounds like the fan is doing strange things, but it appears to be fine. Help? :S
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83hurst-olds
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Re: Weird rattle sound like something stuck in the fan???

Postby 83hurst-olds on Tue Oct 26, 2010 5:07 pm

Clutch fan maybe?

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pontiacgp
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Re: Weird rattle sound like something stuck in the fan???

Postby pontiacgp on Tue Oct 26, 2010 5:30 pm

fan blades loose?
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Bonegrater
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Re: Weird rattle sound like something stuck in the fan???

Postby Bonegrater on Thu Dec 09, 2010 5:15 pm

My car started doing this, and it is the fan hitting the top of the shroud. I don't know why, but it stops after the engine runs for a few minutes. Could this be worn out body bushings allowing the shroud to be low enough to just tick the fan blades? Does anyone know why this would happen? I would like to get it fixed as soon as possible.
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RockSS
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Re: Weird rattle sound like something stuck in the fan???

Postby RockSS on Thu Dec 09, 2010 5:27 pm

It could be the clutch fan wornout I had a similar prob on my elky ... when the car is OFF i repeat OFFjust grab a hold of fan and try to wiggle it if it moves time to replace and yes other things can fatige...
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Peter
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Re: Weird rattle sound like something stuck in the fan???

Postby Peter on Thu Dec 09, 2010 5:54 pm

waterpump bearing a possibility
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G-Body_Vet
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Re: Weird rattle sound like something stuck in the fan???

Postby G-Body_Vet on Thu Dec 09, 2010 6:02 pm

RockSS wrote:It could be the clutch fan wornout I had a similar prob on my elky ... when the car is OFF i repeat OFFjust grab a hold of fan and try to wiggle it if it moves time to replace and yes other things can fatige...


X2. Check for top to bottom and side to side play. Does it also sound like the rpm's are higher or like the engine is dragging? Those fan clutches do go bad. I've never seen one so worn that it would result in nicking the fan shroud though! It should spin freely too. If it doesn't you've managed to turn it into a factory flex fan.

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bill
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Re: Weird rattle sound like something stuck in the fan???

Postby bill on Thu Dec 09, 2010 7:21 pm

G-Body_Vet wrote:
RockSS wrote:It could be the clutch fan wornout I had a similar prob on my elky ... when the car is OFF i repeat OFFjust grab a hold of fan and try to wiggle it if it moves time to replace and yes other things can fatige...


X2. Check for top to bottom and side to side play. Does it also sound like the rpm's are higher or like the engine is dragging? Those fan clutches do go bad. I've never seen one so worn that it would result in nicking the fan shroud though! It should spin freely too. If it doesn't you've managed to turn it into a factory flex fan.


These clutches are fill w/fluid or are spring actuated. They should turn, but with resistance (depending on how cold the air temp, the easier it will spin). A free spinning fan clutch at normal operating temps usually indicates a lack of fluid in the housing or in other cases, the spring inside is broken or weak.
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Bonegrater
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Re: Weird rattle sound like something stuck in the fan???

Postby Bonegrater on Tue Dec 21, 2010 8:57 pm

Sorry it took a while to reply, the fan has no movement at all. None front to back and none side to side. I noticed it had stopped doing it for the last week or so. Then a friend from work rode with me to lunch, and he weighs around 290-300lbs. After he plopped in my seat I fired the car up and it started up again. After he got out it stopped, any ideas?
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Peter
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Re: Weird rattle sound like something stuck in the fan???

Postby Peter on Tue Dec 21, 2010 9:08 pm

Bonegrater wrote:Sorry it took a while to reply, the fan has no movement at all. None front to back and none side to side. I noticed it had stopped doing it for the last week or so. Then a friend from work rode with me to lunch, and he weighs around 290-300lbs. After he plopped in my seat I fired the car up and it started up again. After he got out it stopped, any ideas?


could very well be the body bushings compressing from him getting in the car then the fan hitting the shroud
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82 Cutlass Supreme
3.8 RIP 108032
Olds Rocket 350 with 200-4r
-reman .030 over to 355
viewtopic.php?f=25&t=1995 (build thread here)
88 Cutlass Classic- gutted and gone to rest
01 Bonneville SSEI

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G-Body_Vet
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Re: Weird rattle sound like something stuck in the fan???

Postby G-Body_Vet on Tue Dec 21, 2010 9:08 pm

Take the bellhousing cover off and see if the noise goes away. I just remembered I had this happen in my Lemans. The cover would slightly contact either the converter or flexplate sometimes while it was running. The odd part is that it didn't do it until it got really cold outside. When the car warmed up it would quit. Worth a try.

It sounded like a card stuck in bike spokes, you'd give it gas and it got loud as hell. Like I said though, after the car got warm it didn't do it anymore. It almost sounded like something was hitting the water pump impeller because it had a metallic sound (metal dust cover).
Last edited by G-Body_Vet on Tue Dec 21, 2010 9:21 pm, edited 1 time in total.

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pontiacgp
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Re: Weird rattle sound like something stuck in the fan???

Postby pontiacgp on Tue Dec 21, 2010 9:16 pm

Peter wrote:
Bonegrater wrote:Sorry it took a while to reply, the fan has no movement at all. None front to back and none side to side. I noticed it had stopped doing it for the last week or so. Then a friend from work rode with me to lunch, and he weighs around 290-300lbs. After he plopped in my seat I fired the car up and it started up again. After he got out it stopped, any ideas?


could very well be the body bushings compressing from him getting in the car then the fan hitting the shroud


I was thinking along the same lines but I'd be checking to see how the frame is...it sounds like a body bushing may have eaten through the frame
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G-Body_Vet
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Re: Weird rattle sound like something stuck in the fan???

Postby G-Body_Vet on Tue Dec 21, 2010 9:24 pm

84hurst wrote:The fan shroud is as clean as can be.


This is why I don't think it's the fan contacting anything. The body bushings would have to be really, really bad for that much movement. The only time I had fan to shroud contact was with broken motor mounts on a 400 sbc.

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pontiacgp
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Re: Weird rattle sound like something stuck in the fan???

Postby pontiacgp on Tue Dec 21, 2010 9:30 pm

G-body vet has a good point....84hurst...you need to feed your friend and get him to sit in the car so you can take a good look while the engine is running
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