[racerboy]

When I first start car up, the fan is now hitting the shroud. It’s really loud at first but after car warms up it the sound is reduced, but doesn’t disappear completely.

Any idea what would cause this? I checked and all the bolts are tight. Do I loosen them and try shifting it around?

Sorry if this is something I should’ve posted in the ‘Street’ section.


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[dstryr]

Have you recently done work to the car? Is the fan the correct diameter? Did you have some front end damage that may have shifted your core support? Or worn body bushings crushed and allowing the front to shift? The fan should only bolt on dead center, anything else would be imbalanced and cause more problems.

[racerboy]

No work to front end. Bushings and everything are relatively new (maybe 5-7 yr old). About the only thing different are wheels/tires, but they are stock 14” JT wheels.


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[johnta1]

How was the car jacked up to change the wheels?

[racerboy]

Was done on a lift


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[johnta1]

Possibly the lift arms weren't lifting by the frame?
Tweaking the body to frame?

[DOC]

Learned this in tech school in the 80's. For a RWD car: Always check for a rotten body bushing. Not all rubber is created equal. if hitting the top of the shroud, check your transmission mount. Hitting sides of shroud, check motor mounts, hitting bottom of shroud, check body bushings and motor mounts. Hope this helps a little.

[DavesGTO]

I am just finishing putting my car back together and am having this issue but much worse. My 2 cents, trans mount is too thick it can force the fan lower by forcing the engine down up front enough to hit. Motor mounts for me same thing hits bottom of the shroud usually if the mounts break, my past experience. I am starting to think that in my case I needed to shim the core support lower to give me more room at the bottom. If you are hitting the top of the shroud maybe you could check the core support bushings in case it has dropped?


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[tom s]

I had that issue with my 69 Judge,2 things,trans mount was too thick and the frame rails were pushed up from being jacked up in the wrong place.Took it to a body shop and he pulled the rail down and then I shaved the trans mount on a band saw and life was good.Tom

[racerboy]

Thanks guys. I think the fan was hitting the bottom of the shroud but will double check. Does it make any sense that it is much louder when I first start the car up cold?


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[Joe's Garage]

They spin faster and harder (and lots of time a little bit out-of-round and out-of-balance) when the fluid is thick and cold and has settled overnight (or over some period of sitting).

If it's an older, well-used set-up, they can become worn and the fan actually settles down and forward further at a bit of an angle when they sit for awhile.

That's why clutch-fans roar when you first start them up - the fluid is thick and hasn't circulated thru their inner workings to allow them to slip as designed. Once the fluid circulates and thins a little they loosen up and 'self-balance' and slip like they should. And they quiet down - until you get them up to the temperature where they re-engage because of the engine temp.

If the fan is barely touching the shroud, it barely touches less often. So the noise is lessened.

We've run across several like this. There was always another issue like worn motor mounts or radiator support mounts that caused the fan to be too close to the shroud.

Sometimes, on a fairly recent engine install, you can loosen the thru-bolts on the mounts, lift the engine slightly, reposition it (the engine) to gain whatever clearance is possible, and re-tighten the bolts.

However, if this is a new noise, following the car being lifted improperly as others have noted, the repair may be a bit more involved.

We had one 1970 GTO with the factory stainless-steel flex-fan where the shroud was distorted and out-of-round and the fan touched under acceleration because of weak motor mounts. That would be another thing to check.

And don't forget to check your lower shroud bolts to make sure they are installed and tight and the shroud is positioned correctly.

Good luck!

[Gastiresandoil]

Since it appears that either of the cars you are talking about are manual tranny cars, clutch fan and fluid can be ruled out. If you are referring to another car with an auto tranny, disregard the previous statement. I can't tell exactly if you are talking about one of the cars in your signature or another car. I digress

I had this same issue a few years back when I replaced a flex fan (smaller diameter than stock) with the original 5 blade fan, manual tranny car at that. The issue however wasn't the fan, but the tranny mount. It was only after replacing the fan that I realized the tranny mount was too tall and was angling the engine downward in the front, pushing the fan into the lower fan shroud. Not saying this is the issue, just my experience with the shroud contacting the fan.

I also will say that I can't see the radiator/fan shroud mounting bushings causing the issue since the fan shroud would be hitting the fan on the top side of the shroud if the bushings below the shroud were failing.

Tranny mount, motor mount or bent frame would be the best places to start looking for irregularities, IMO.

[DavesGTO]

If anyone is interested or has the need to check the dimensions on a frame, I have a copy of the print for the frame for 1970 Tempest, GTO & Lemans in case you don't have one. I don't maintain image hosting privileges anywhere but I can email if anyone would be willing to link it here. I use the tap-a-talk app on the phone for photos since they will host the image but that's not a good choice for this.

[orangegtojudge]

I encountered this issue with a car that I had many years ago. Both sides of the frame the the trans crossmember rests on were bent up. Car had problems been on a dirt road several times and the crossmember bottomed out and bent the frame rails up. I made a tool to fix this and no more problems. Thought I would never use this tool again and hung it on the wall in the shop. Bought another 69 Judge and the U joint was rubbing on the floor board during acceleration. Used this same tool to fix this problem.