jsabatini

'87 911 started doing this a few weeks ago. After 20 mile highway drive as I was exiting highway when I downshifted and blipped throttle I heard a whine that sound like the loose fan belt noise you hear on cars. As I was at the light I blipped the throttle a few more times and it made the noise again. Regular driving no noise majority of the time. Occasionally get a brief little whine on an upshift.

Still does this intermittently, but not all the time. A few days ago my car mentor, father-in-law was over and I could not get it to do it. Did it again yesterday so I stopped by his house and it made the noise a couple of times but not continuously.

Any ideas would be appreciated.

theiceman

At first blush it sounds like an alternator bearing. If it changes with engine speed I would go with that to start with if you don't have ac.
If you have ac just take that belt off and see if it still does it.

jsabatini

Thanks Iceman

It does not change with speed, it just goes away. Yesterday in FIL's driveway I was able to get it to make the noise by blipping the throttle from the engine bay. Did it a few times and heard the noise, then it quit making the noise.

Do have a/c. So if I take the a/c belt off and the noise goes away, does that mean alt bearing?

oldskewel

Could it be the (rear) heater blower? When mine went out, it made a high pitched intermittent whine. Just turn off your heater next time it happens to confirm.

jsabatini

Thanks! Being in sunny Florida I do not use the heater very often. Did use it within the past month, but pretty sure it is back in the off position. But will double check.

theiceman

If you take off the ac belt and then it stops. It gonna be your ac clutch bearing. If it still does it could be alt bearing.

Steam Driver

I vote for Iceman's A/C clutch bearing; my CRX has been doing that for years!

jsabatini

Being in Florida this time of year I am not using the a/c. Does that matter, the belt is connected, but I am not using the a/c?

theiceman

the bearing still has to spin ,it just doesnt engage the clutch
given the 10 minutes it takes I would remove it just to see and remove all doubt.

jsabatini

Took your advice, that's why I asked in the first place, and removed the a/c belt. Good reason to drive the 911 to work today! After the 25 mile commute, no whine, so hopefully that's what it was.

Will keep driving to see if I hear it again.

Thanks for the advice!!

theiceman

Still means you gotta fix it tho .. id hate to suffer Florida heat with no AC .. YUK ...

jsabatini

Florida heat typically means keep the sporty car in the garage.

However, driving home just now and the intermittent whine is back, so I guess the a/c clutch is OK.

theiceman

then looks like could be the alt bearing.

here is the problem ..
if it was not intermittent you could take the alternator fan off for a couple minutes to see.. it would not cool and you would have no alternaor but for 2 mintes who cares

with it intermittent that becomes harder

my suggestion is just drive it till it becomes less intermitent.

jsabatini

This thing is driving me nuts, drove it last night and it did it from the beginning. Drive it today hoping it will do it because my mechanic is close to the office, not a peep to or from the office.

theiceman

I hate that stuff. If it's gonna break , break for Christ's sake