Hot Fan Ringing?

[Pstallo]

So, it's in the mid 90's today and I was driving the car about 20 minutes. Started the car up after being parked about 15 minutes and it sounds like the fan is hitting the fan housing (metallic rattling/ringing). It actually sounds like raccoons are knife-fighting inside a trash can.

I figured the fan must have expanded against the housing and let the car cool off. Started it up and the sound went away.

Has anyone every had that happen? Do you just grind the tips of the fan down a millimeter or two or something?

[efhughes3]

I'd spend a bit more time exploring what caused this issue to crop up out of the blue. You may have a failing alternator or something loosened in its mounting.

There are many, many thousands of these cars that have never required grinding fan blades down to avoid interference.

[tirwin]

Seems like I've read here that bearing failure of the alternator can cause this.

That is one of the best sound descriptions I've ever read though!

[darrin]

agree with the failing alt bearing possibility -- get it checked/fixed asap -- next step on a failing alt bearing is having it seize, break the alt/fan belt, and overheat your engine.

[steely]

I don't like the grinding idea either, they can fracture too easily.
Make sure there is / is not marking on the housing from the fan.
Check that the housing is down tight, and that the ALT hardware and bearing are good.
I've heard failing chain tensioner noise described as chains rattling in a garbage pail (old skool), are you sure that's not it? Good luck

[DRACO A5OG]

Post a pic of the fan housing, it will show if the fan hit the housing for sure.

[Pstallo]

I attached a pic of the fan housing. There's only one mark on it (red arrow). It's definitely a scrape.

Would a bad alternator bearing cause the fan to shift and scrape or would the rattling sound simply be the bearing itself making a racket?

[DRACO A5OG]

When you have time, remove the belt and spin by hand. it will be pretty evident.

[Quicksilver]

from your picture it looks like the shroud may have slipped so it is rubbing on the crank pulley. If so you need to loosen the band clamp and push the shroud back.

[Discseven]

Ps... use mirror to check inside housing at around 1 o'clock. Original magnesium housings eventually fail / crack / warp. When they go out of round, fan makes contact. If ignored, fan tips will burn but do so at the rear edge---so not visible. Also, provided enough frictional heat, gas trapped inside fan's metal will expand... blister... explode. Catch this early and only part cost is replacement housing. Makes high pitch bell ringing sound.

[Pstallo]

Okay, I was finally able to take off the v-belt and spin the alternator and it rotates smoothly.

I DID notice, however, a part of the pulley the v-belt goes on that looks bent out of place. The little red arrow in the pic is pointing at it. It bends the pulley precariously close to the housing.

Any thoughts on that?

[SoCalSK8r]

Originally Posted by Quicksilver

from your picture it looks like the shroud may have slipped so it is rubbing on the crank pulley. If so you need to loosen the band clamp and push the shroud back.

Quicksilver is spot on, this happened to me when I replaced he alternator and didn't have it properly seated.


Sent from my iPhone using Tapatalk

[jason2guy]

you need to replace that crank pulley, not sure its related to the scraping but its toast
surely the heat wasnt doing it any favors, the way the alt is attached to the housing
can influence the fan clearance. if you work on this car yourself- pull the alternator and give things a look.
make sure its snug

[Pstallo]

I will try loosening the band clamp and see if I can shove the housing back. I see the bolt on the band clamp at about 10:00--is that the only bolt that needs to be loosened to be able to shove the housing back?

Originally Posted by SoCalSK8r

Quicksilver is spot on, this happened to me when I replaced he alternator and didn't have it properly seated.


Sent from my iPhone using Tapatalk

[theiceman]

yeah that's the only one .remove and reseat

[whiz05403]

This has happened to me and it was the small lock nuts on the back the housing coming loose. I loosened the strap, tilted the assembly towards me and replaced the old lock nuts with fresh ones, fixed!

[Pstallo]

I will definitely try that tomorrow. I tried loosening the housing, but couldn't get it to scoot back any significant distance. Maybe loosening the bolts and tilting will at least keep it from rattling against the drive pulley until I can get it replaced.

Originally Posted by whiz05403

This has happened to me and it was the small lock nuts on the back the housing coming loose. I loosened the strap, tilted the assembly towards me and replaced the old lock nuts with fresh ones, fixed!

[Pstallo]

BTW, anybody ever had the drive pulley replaced? Any cost estimates on that?

[Koizumi]

Mine makes a bell sound at start up for a few seconds. No scraping evidence.

[zedsn]

The belt may have gotten too tight from the heat and put extra stress on the alternator bearing. Maybe add a shim to the insdie and see if the noise goes away.