69COU

Having a good old drive down the M40 to Berkshire in the hot sun with air con on full suddenly the red lights ( Central light and fan belt light came on ) Switched off central warning light slowed down, turned off air con , but the other fan belt light stayed on for about 5 minutes. Eventully as i behan to worry light went out.

This repeated about 3 times every 15 minutes that day but no sign of any of the belts being loose or broken when i stopped.

It has not reoccured since or the next couple of times i have used the car since.

Not sure if i put it down to belt(s) slipping due to heat and having being driving through London traffic for about an hour and a half before about another hour on motorway (A bit faster!!)

If it is a belt slipping slightly will this cause any damage to the car in the short term.
Alternatively do i send it into garage before undertaking any long trips?

maverick

It could be your belt tensioner going out. It is the small wheel that sits against the smaller belt on the left side, they are prone to failing.
Maverick

maverick

I should have said belt tensioner sensor.
Maverick

JBH

Mine is currently doing the same thing and Maverick has it exactly right. I can poke at sensor and the light goes out. Should be an easy replacement.

Adrian

The most common problem with these sensors is not the actual sensor but the connector at the sensor. Do not replace the sensor and waste money until you have checked the connector. I have known a few people that have and the problem comes back. In the end they found corroded wiring inside the connector. There is a little microswitch activated by the arm. Give this a bit of a clean with contact cleaner as well. They can get filled up with general engine gunk.
Ciao,
Adrian
911C4

maverick

I had mine repalced due to the small wheel falling off! The part only cost $64.37 + labor
Maverick

bonehead

I've been having this issue of late. Light will go on and off intermittently. Engine temps seem to be relatively steady but it's obviously worrisome when it happens. Belt appears to be in good condition. What cleaner would everyone recommend before I buy a new sensor?

Metal Guru

Electrical contact cleaner. You probably could get a can from Amazon or an electrical supply house.
My experience is that once there's pitting or carbon on the contacts, the sensor is toast but it's worth a try.

bonehead

Thanks Paul.

Haven't looked closely at the sensor, but does it need to come out or do I just have to pull the connection off the top and spray the contacts?

Max964t36

Had a problem with it many years ago ... removed = no problems anymore

Metal Guru

All I've ever had to do to mine was lube the pulley.
Apparently you will be going where no other board member has gone when you disassemble it Just make sure that no tiny springs go flying into the different dimension that they always seem to travel to when disassembling.

rstarga

It is always wise to check your crank pulley for any wobble. My light came on once and the pulley had loosened and the belt broke the sensor. Luckily I caught it before it had damaged the crank end.

Metal Guru

Good catch. I hadn't thought about that.
Wonder why Porsche didn't use a Locktite patch on that bolt.

JasonAndreas

A pencil eraser works wonders for cleaning carbon from pin contacts although it can take some finagling. The inside is simple cherry switch and a large spring. I have photos posted here but the Rennlist member sites are down for the moment.