Urgent!!! Fan Belt Warning Light

wastintime · 10-01-2003, 04:37 PM

Something always has to go wrong at night when everything is closed, and you're about to drive 1700 miles right?

Ok, the car has been running like a champ since the oil change this morning. I just took an easy drive to an ATM and after leaving the fan belt warning light came on. It never went out until I got home. Turning the car off and then back on again didn't help for about ten minutes, then the light went out. I played with the throttle though, and as soon as the engine hits 3,000 RPMs it comes back on.

The owners manual says that if the fan belt light comes on then the belt is broken. Both belts appear to be in fine condition, the teeth look fine, and neither one seems loose. The rear one looks older then the front one, but i can't see how that really matters.

I have to leave in 6 hours so, unless someone thinks this is really a problem or has the potential to be a problem, I think I'm just going to chance it and go.

Which brings me to my next question... does anyone know a good Porsche shop near Buckingham PA that could look at it if the problem persists?

Thanks,
Andrew

MotoSook · 10-01-2003, 05:01 PM

What!!? Fan belt light? It's probably due to a bad exhaust gasket bearing.

SteveStromberg · 10-01-2003, 05:07 PM

Take a close look at the belt- If it looks ok, you should be fine. Just to be safe you could install the new belt that you have in the boot.I would check the roller wheel and wiring. Steve

Rot 911 · 10-01-2003, 05:12 PM

Waste do you mean the alternator/battery warning light is coming on? Sounds to me like you may have either a loose belt or an alternator getting ready to call it quits on you. Do you have a multimeter handy to check and see if you are getting a charge to the battery?

wastintime · 10-01-2003, 05:16 PM

No, the alternator/battery warning light is definitely not on. Just the Fan belt warning light. Both belts seem to have good tension.

my meter is at my parents house... but I'm pretty sure the battery is charging. I wish I knew what the sensor feeds off of, becuase again, according to the manual it's telling me that the belts have broken, but they clearly are not broken, and they're turning everything. I don't think they're loose, you can usually look at a loose belt and spot it right away, these don't seem to be fluctuating up and down like loose belts do.

wastintime · 10-01-2003, 05:16 PM

btw, the car is a 964, I don't know if earlier cars didn't have fan belt warning lights

Rot 911 · 10-01-2003, 05:21 PM

Sorry I don't know squat about 964, but if all it really does is warn you about a broken fan belt and yours is intact and your alternator warning light is not on I wouldn't get too worried about it. Just carry a spare belt with you and check at every stop to insure the one on the car is still there.

rattlsnak · rattlsnak's Garage

The sensor looks like a little wheel on a bracket. The wheel rides on the outside of the belt, (the fan belt, not the alt belt). If the belt loses tension (breaks) the the wheel moves further out and it triggers the switch and the light comes on. If the belts are indeed tight then its probably a faulty sensor, and I would drive it, just watch your engine temps. You can move it around in and out to see if its maybe a glitch. If you lose the alt belt, then the battery light will come on.
Hope that helps..
Marc

wastintime · 10-01-2003, 05:36 PM

I unfortunately don't have a spare belt, or a tool kit (not the brigtest thing I know, but this wasn't exactly a planned trip, and my car didn't have a toolkit when I bought it) and I don't know where to get one or the tools to change one at 9:30 at night, so I guess I'll just have to chance it, and get a new one put on in PA, lol, providing I make it, which I hope I will.

maxnine11 · maxnine11's Garage

as Steve mentioned, check the connections at the roller / sensor at the fan belt. here is a picture of the sensor:

if your belt breaks, there is no pressure on the roller, which triggers the warning light.
if your belt is fine, you may have a failed sensor, or a bad connection.

EDIT: this may help you too: 993 belt tech article
max

wastintime · 10-01-2003, 06:26 PM

jeez... after reading that I'm hoping I never have to replace the belt... I'm starting to like my old 912 again...

wastintime · 10-01-2003, 09:46 PM

well, I just drove the car about 25 miles, and couldn't get the light to come back on, so i'm guessing i'm alright. The belt does feel just a tad loose, so I'm going to have it swapped out when I get to PA, thanks guys.

Andrew

ischmitz · ischmitz's Garage

The fan belt warning sensor is a simple switch. CLOSED when the fan belt is on and OPEN when the belt is missing. A lose fan belt would not trigger that thing by any chance. The lever needs to move about an inch to the right before it opens the switch. If the belt is so sloopy that it'd allow the switch on the sensor to open you could take the belt off the pully without using tools.

If there is any bad contact somewhere down the line to the central informer the fan belt warning lamp gets swithed on by the central informer. My guess is that you have poor connection somewhere (corrosion), a bad cable or a bad switch.

Don't let that slip. If the belt does brake its important to react prompty and shut the engine down. You don't want to wait until your raised oil temps tells you that the cylinders and the heads are already cooked because there was no airflow for a while.

Ingo

MotoSook · 10-01-2003, 10:44 PM

Phew! Thought I was going to have to drop my motor to find that switch! But thank goodness it is a NINESIXFOUR!