help with noise

I allways get worried when my car is going into my local OPC! I started to here a eeeeee noise from the rear when pulling away when the car was cold. It started in winter and i thought it was just a belt. I did drop into my local indi and at the time they thought it was something small, can't remember what they sugested it could be. Anyway the noise only lasted for a few minutes when cold and as all but gone now the warmer weather is here. When i say a few minutes i mean the noise only happens in the first few minutes of the car running, when pulling away in first the noise last for about 2 seconds. My extended Porsche warranty is up at the end of June so i thought i better get it looked at. I droped into my local indi again for some advice but this time thay have mentioned it could be a rear sprocket and gearbox off job. My local indi took the car for a quick test but couldn't get it to make the noise, I knew they wouldn't. My worry is the OPC won't find anything and charge me for time served. Then the problem will come back in winter when the cars out of warranty. I know it's hard to imagine the noise but as anyone had the same noise? Sorry for the long winded thread Thanks for any help Chris

Hi Chris If your car is still doing it when cold why not leave your car with the OPC overnight and get them to test drive it cold, just a thought.

If it sounds like a screeching belt, then it might be the polyrib drive belt slipping when cold. When was it last changed? It should be done at 48000.

Does it happen just as you are engaging the clutch? If so, mine has made that same noise (albeit only lasting for about 1s), randomly but only about 2 or 3 times over the last 2 years.

It only happens from cold and when i'm pulling away, it's worse under load, ie: if i'm doing a hill start. It sounds like a belt to me and it's funny it only started in the winter. My worry is it sometimes doesn't happen at all from cold now it's got a bit warmer and if it does it only does it when i pull away the first time then when i stop at a junction and pull away no noise. I will be leaving it overnight at the OPC just hope i'm not waisting time and money, being a Yorkshireman i hate that! The other thing what could happen if I just leave it? Thanks guys for the help please keep the ideas comming.

Update. I took the car for a quick test yesterday and couldn't get the screech to happen. I'm starting to think it's a waist of time taking it into the OPC. My only concern is the warranty, it runs out in June! I should have taken the car in when it was happening regular in winter but i was realy busy at work and it still only happened a couple of times when cold and sounded like a belt. What would you do! Thanks everyone.

If it was me I'd change the belt. While doing it I would check the tensioner rollers too. The belts are only about £25, it takes less than 1/2 hr, and it will eliminate it as a possibility.

Richard thanks for the advice. I'll give my indi a ring and get the belt changed, could you clarify for a non-techy which belt, sorry if it's obvious! again thanks for the help.

It's the one which drives all the ancillaries - alternator, water pump, power steering pump, and aircon pump.

I had a similar noise in mine last year. It was pully No. 8 in the diagraim above that was causing the noise. It was intermittent at first then all the time. When the belt was off I could just feel a very slight grating of the pull which was hadly distinguishable. Did the whole job myself in about 1 hour and cost a total of approx £75.

I had a similar noise on my C4S about two years ago and posted a similar question on the forum. My belts were changed and the noise was still there (only when the car was cold and only for a few minutes). It was found in the end that there was a problem with the exhaust - the sound sounded like it was coming from the drivers side - with all the windows down to listen for it, but in the end they found that it was coming from the other side and one side of the exhaust had to be changed. Porsche covered this cost in full with the labour (which is good of them as the exhaust is not covered under warranty) and the fault never came back. My car has had a couple of faults that have required the car to be left over night with the dealer (I asked them to take the car home with them on an evening to replicate a rattle - which they did) and it is certainly worth it given the cost of doing the work outside a lapsed warranty. I have a print out at home of the exact work that they did (or a least of the cold rattle part they replaced) and will post this evening if it will help.

Thanks again to all, I think the belt was changed at a main service back in Jan 08 part number P996.107.225.53 is down as being done. It had a new Porsche switchable sport exhaust fitted Dec 06, dilloncallum was yours the sports exhaust? I've tried realy hard to get the noise to happen again and nothing! I hate things like this they bug the hell out of me!!!

That part number is the oil filter.

silly me! and Richard you must sleep with your Porsche! number P996.102.151.66

Mine was (is) the standard non sport exhaust. This was changed at 20,000 miles (by Porsche) on the left side (passenger) although from inside the car the noise sounded like it was coming from the drivers side. I tried in vain to get the noise to happen 'on command' to no avail, but worked out that the car had to be cold (and a cold evening before) to make it happen. Oddly, in December it went in for another noise (which I had asked the dealer to find on a few occassions before - but the car failed to do it 'on command') and Porsche found that three 'spot welds' had failed behind the lights (and the engine had to come out to repair it). I never had the time to stick this episode on the forum. These noises can be expensive.