Engine noise 3.2L

steven12xu · 11-25-2010, 09:14 AM

I was driving yesterday and a banging noise started around my cooling fan. There was no loss of oil or oil pressure and the car starts and runs smoothly but the temperature started to rise.
The noise increases with the engine speed so it's not the criuse control banging itself like on a 944 that I had.
Alternator or fan bearings?
It's an '86 911 with 132,000 miles. A trailer ride home is $860 and I'm in rural west Alabama. My trusted mechanic is in Marietta, Ga.
Anybody know a reliable mechanic in Tuscaloosa? The ones I used when I lived there were not.
Turkey
Lurkey!

Cattler · Cattler's Garage

Banging noise like metal on metal? Could be the fan blades hitting on the alternator mounting frame. AMHIK.

I'd check the inside of the housing for marks--shiny shallow cuts. Look also for potentially chipped fan blades or small hairline cracks in the housing.

If you don't see those, its something else.

David

TRE Cup · TRE Cup's Garage

Could be a cracked air director blade on the alternator cone. This piece of plastic is bolted to the back of the alternator. There are a couple of curved metal vanes pop riveted to it. If one of those metal pieces are cracked, it will vibrate and make a racket similar to hitting an empty coffee can with a knife.
You MIGHT be able to see the vanes thru the fan and poke at them with a long skinny screwdriver. If intact, there will be very little flexibility to the touch. If cracked, you can drive the car with no worries till you can take it to your tech
check it out and report back

Joe Bob · Joe Bob's Garage

My alternator pulley put up a hell of a racket when it died......

steven12xu · 09:32 AM

Thanks for the quick answers. I'll see if I can get a ride to Tuscaloosa today to check it out before I get it towed.
It does sound like something banging on a coffee can. With stacks of hundreds floating away into the distance as the sound subsides.

steven12xu · 11-25-2010, 03:40 PM

I got to go and check out my car in the daylight. No scraping in the fan housing or noisy bearings in the fan/alternator. My mechanic suggested that it may be a rocker arm or rod bearing now that the f/a is confirmed to be OK.
My neices' husband is hauling me home and saving the tow fee.
Thanks for your help with my question.

Hodgey · Hodgey's Garage

you could always try Eurasian Auto in Birmingham Al and speak to Casey Hooper.....they are absolutely stellar Porsche people......

ruby911 · ruby911's Garage

May be a stretch, but I had my car in the shop a few weeks ago (and again today, but that is a different story!) and while they were changing out the fan belt, they noticed the pulley had loosened and was actually spinning on the fan. So, in theory the pulley was moving at a faster rate than the fan, possibly causing the car to run hot. Fortunately it was caught because it was slowly cutting a grove all the way thorugh the fan. Had to buy.install new fan and pulley to correct it. May be worth a look.
- Farrell