Anyone get an alt fan rattle high operating temps?
 

It was over 90 on my commute home last night in stop and go traffic. Oil temps rose not quite triggering the front oil cooler fan which is triggered at 244F IIRC but I was clsoing in on the 250F hash mark (210F being the next lower mark that I always consider "normal operating temp" just slightly above).

In 1st gear I could hear a faint alt fan rattle. Had similar problem last year when ambients were 104. Changed alt belt and all was well. I don't think the belt is loose again but wondering if this recurring rattle at high operating temp is normal or not. I always get nervous with any new sounds! BTW A/C compressor renniing full tilt in both instances.

Do the belts expand and slip at high operating temps?

165k on the clock. Service records indicate alternator was replaced at 100k.

Thanks!

Is there any chafing marks of the fan on the housing wall...?
May be the fan shaft bearing is on his way...

My fan gets a little noiser at high temps.

Hadthe alternator rebuilt with new bearings and the noise is still the same.

I think it's the belt expanding/slipping a little in the heat.

This is what I was thinking. If others weigh in with similar experience, I sure will feel better. On the other hand, if something is wrong I'd like to fix it ASAP.

are you using the conti belt?

OEM Porsche belts from the local stealership. Is this good or bad?

You may have tightened the fan strap too tight. It gets out of round when that happens and makes a horrible screetching noise... don't ask me how I know... It may be that it is expanding due to heat and slightly rubbing... *shrug* just a guess.

-michael

oem belts are great. I'd steal a page from mr. drago's playbook, and try running the engine a short while without any belts and see if the noise goes away. You can also try spinning the fan without the belt to see if you can hear any scraping or knocking.