Alternator DIY?

In which case, you won't want to know that a new alternator is £700+ A refurb by a Bosch specialist will cost about £100. Physically removing / refitting isn't a huge job if you are handy with tools.

So I'm driving along and all of a sudden the Ipod goes quiet like my old dads car radio used to go silent when going under a bridge back in the day. I look at the PCM to see a blank screen. A beep is heard and a red batter/generator warning pops up. the music and screen returns. It happens again and when it occurs for the 3rd time I notice a 1 amp blip upwards on the amp meter. Then the fading in and out of the PCM stops but the dash warning goes on and off until I arrive home. I put a very rudimentary tester on the battery which checks alternator and that reads ok. I have done another run and monitored the amps which are constant at about 13.5 apart from the blip to 14.5 every now and then. This time I don't just get a battery/generator warning light I momentarily get the Tip has gone to emergency run but that goes as soon as it appears. I have convinced myself it must be the alternator and will get a proper test done. If it is a new alternator (unless someone else has an alternative suggestion) how hard is a DIY replacement. Anyone done one? Started a new business last week so the last thing I wanted was a large bill so soon!!! RB

Could be just the regulator on the alternator which is about £40 to replace yourself. Did it on my C4 inc. removing the alternator which was a 20 min job, honestly! Mine showed only 10 to 12 volts when engine running so battery discharged, on start up voltage wavered from 13 volts down to 10 volts.

I agree with Jon. This might help: http://forums.pelicanparts.com/porsche-996-997-forum/408495-alternator-repair-regulator-replacement.html There is a DIY from Min on removing the alternator (albeit on a Turbo) in the Technical Articles section.

Thanks Fella's The link to the alternator removal is invaluable and looking at it leads me to believe that I can manage the job myself. The regulator suggestion is a very valid one as the battery does seem to charge OK but the power spiking intermittently does indicate the issue could well be there. In terms of the regulator, normal suppliers? And I assume it would pay to remove the alternator for the part number first to stand the best chance of getting the correct one? RB

I think you can safely go out and get the Bosch Part number: F 00M 145 225, which replaces F 00M 145 350. Porsche also supply it (Part No: 000.043.206.37) at £68.80+VAT, so you can use that as a benchmark when shopping around. Just Google the Bosch number, and you should find one a fair bit cheaper

I got the regulator for £28+vat 2 years ago from the wholesalers.

Thanks again Richard et al, Having poured over the info in the links I'm now 99.9% sure its a faulty regulator being effected by the cars running temperature. When I first suffered the warning the car had got to operating temperature and further down the road and after the spoiler deployed I imagine the cooling effect across the alternator reduced the incidences of the spike and warning light. I got stuck in heavy traffic further along the journey and the problem resurfaced as the car had no air cooling but went away again once I was hurtling along at 70 MPH (Ah hem!) Right, where's me spanners

You were right Richard, Europarts have the Bosche regulator at £43.45 inc of Vat. As you say a good deal cheaper. RB

Richard and others, FYI Bosch have re-numbered the regulator to F 00M 144 136-395. RB

Hi, Today the dashboard showed up a fault with the generator and the ! came on. Car ran ok for a while then a medley of lights came up and then car seemed to enter limp mode. Managed to get home. Stopped car on drive and then tried to restart, battery appears to be flat. The battery had been fine and is only 6 months old. Showed 11.6 volts when tested with a meter. Looking back over all the servicing paperwork, mine and years back, can't see the alternator was ever changed and I have to say it looks like the original. Any thoughts on replacing the voltage regulator to start with (I'll check all wiring connectors before I do anything) or should I go for a new alternator? Have seen various feeds on VR and new or recon alternators. Any thoughts and helpful tips are welcome please. Thank you Adrian

I would certainly check the regulator first, it's very likely to be the cause (the symptoms are classic) If you're not far from North London, I actually have an alternator with a new regulator installed that I have had lying around for years which you can try installing to see if that's it.

Thanks to those of you who've replied thus far, very helpful and I'll tackle the car this evening after work. Will check a few things before buying any parts. Cheers Adrian

When the regulator is on its way out, it can sometimes also spike the voltage past 16V which can do bad things to the electronics so try not to use the car until you fix it.

Thank you Minny, great advice.

I did mine (Turbo but it's the same kit) last year using the Pelican Parts Guide. Took 2 to 3 hours but I went slow. Things that might help: 1 - The forward most retention bolt is a swine to get to and to get enough leverage on 2 - The accessory belt needs a long bar (or scaffold pole) and/or another person to get the belt back onto and around the tension wheels 3 - Some plastic clips and hoses will be brittle so take care. It is easy enough. Good luck.

I had similar last year, when it was serviced I was advised that the alternator was on the way out, but should be OK for a while and then 2 weeks later on the way to simply Porsche I got alternator error on the dash. I had to be towed home and as a quick fix I bought a £139 new unit off EBay, fitted without too much hassle,although getting the bush on the back of the old one to go back far enough was a pain and took a lot of persuading (Many YouTube videos available on the process). The one I fitted has been perfect now for nearly a year and 5000 miles and has the advantage over the old one of having a clutch in the pulley, which at first scared me as when the car first starts the voltmeter drops and then after a few seconds ramps up. I looked at my old alternator and the only thing I could see failing is the regulator so I have bought one and fitted it, but have no means of testing other than fitting it to the car. I believe the failure of my old one was due to the amount of oil and gunge on it from when my AOS failed.

I hope that all of you who replied to my request for help receive a great big thank you from me......thank you. Oddly enough the problem seems to have gone away but I plan on fitting a new or recon alternator, belt and new pulley wheels in the next week or so. I'm monitoring the car right now. Cheers!

I would suggest replacing the voltage regulator as has been suggested and report back. It does not sound like the alternator wiring breaking down itself is an issue so try the simple regulator replacement first. I have replaced this myself using part number ‘Bosch F00M144136‘ from whatever reputable source you select. I believe you can very easily buy for under £40. Autodoc have this part right now for £28 for example, but are not the fastest for delivery times as they are in Germany. The only thing to be careful of in addition to the of guides online for this is to be careful around the small coolant host which was mentioned by an earlier post - part number 996.106.223.52 is what I replaced when doing mine just to be safe. The plastic pipe joiner goes brittle over the years and can break very easily but it is only a small pipe so you would not lose much coolant when replacing that. Good luck J

It may be a little late but I can also confirm that the alternator removal and replacement is a fairly easy day job for the practically minded. As stated previously, the most difficult part was once the unit had been unbolted, finding the right position by twisting to get it out of the engine area past everything else. Tricky, frustrating and can get a few scratches on the arms. By obtaining a reconditioned unit and doing the job yourself you certainly do save on costs.