993James993

I just had my car serviced by a very experience and competent Porsche mechanic whom I trust completely. When the car was ready he mentioned that the alternator bearings are noisy. ( I could hear something making an unusual noice for the past two months. I thought it was related to the cooling fan.)

My mechanic said the car is ok to drive around town for now but that he recommends addressing this prior to any road trips or a two day DE event coming up in September.

We discussed the amount of labor involved and he recommends replacing the alternator with a new one (not rebuilt) made by "Valero" or "Alero." He indicated that he has had bad luck with rebuilt alternators and excellent luck with the Valero units. I checked on Pelican and only found the rebuilt Bosch units. He is going to get me a price next week but I wanted to ask the experts if anyone has any experience with this.

Thanks for you help!

Jim

Terry Adams

I just had my original alternator replaced at 154K miles. System not charging, battery dead after 1 week. New OEM part # 964603 156AX. Wonder what part bin that came out of? $278 part. 3 hours labor, including replace fan hub bearing and noisy belt sensor.

geolab

ax means it is core exchange against old part. But for $278, that was a steal. Normally exchange is priced around $700, and brand new around 1k. Terry you had an excellent deal.

Terry Adams

Thanks geolab. I feel good! It was my independent (RMG Sunnyvale for you south SF Bay Area RL).

Garth S

If you are into DIY, it is not difficult to pull the alternator and have both bearings replaced ... and screw in a new brush set/regulator at the same time: I only did the regulator for $20, as the bearings were fine - but another R'lister reported doing all for $50.
Rather than replace the fan bearing and tension alarm roller, go to the RS hub for less .... and delete the second belt.

JasonAndreas

There seems to be huge difference between the quality of rebuilt Bosch alternators available directly from Porsche and those from aftermarket suppliers. I too have heard of nothing but problems with the non-Porsche sourced rebuilds. After reading Walrod's thread on rebuilding and doing some digging I've discovered the price of bearings and brushes is all over the place ($10 vs. $70) and I'm guessing the aftermarket rebuilders are using the absolute cheapest part available (Chinese sourced brushes). Unfortunately if you are using an independent mechanic there really is no guarantee that what they are selling you as OEM has any resemblance to the original OE part.

$278.21USD is MSRP (from the June price list) in North America so Sunset Imports, etc. should have it cheaper?

ca993twin

OT:... time for a nice upgrade "while you;re in there". Get the RS pulleys, and clean-up and paint your fan and housing. I wish I had done all that when I had mine apart. Just a thought.

993James993

Thanks everyone! I'm waiting to hear from Sunset on the alternator and I will definately go with the RS pulleys Steve.

993James993

Sunset came in very low on the rebuilt alternator. I think I will go this route once I confirm that it is a unit rebuilt by Bosch. They also offered to order a brand new Bosch unit from Germany for just under $800.00.

To convert to the RS Pulley what all do I need?

For those of you who have done this, would you recommend this as a first DIY? My son thinks we should tackle it and in theory I agree. My reluctance is that I don't have a garage to work in, and I need the car as my daily driven when I am home, which is usually just on weekends.

Thanks again!

ca993twin

James,
I'm a doofus, so the alternator replacement would be too much for me to handle. But there are probably good instructions on the DIY webstie (that I never remember the link to... is it a sticky on the top of this forum?). I would worry about trying to get this work done on a tight schedule... it seems that its about a 3 hour job for a mechanic, and there's some special trick to taking the pulley off. I would however seriously recommend painting or cleaning the fan and housing... it is a huge visual improvement.

The RS pully just simplifies the belts... instead of a seperate belt to drive the alternator, and another to drive the fan, the functions are combined into a single belt that drives both... basically the alternator will be driven a small bit slower, and that "belt sensor" gizmo can siply be removed, since it is no longer needed (if the belt breaks, now the alternator light will be your warning). So, there is a massive weight savings (1 belt and the tensioner), plus some massive performance gains from the less drag with the alternator turning a bit more slowly (0.01 hp, easy).

But I'm a self proclaimed doofus.

Mike J

I just did one with a fellow rennlister (Hans might chime in) and it was not too bad. The hardest parts are picky work on the power cables to the alternator...there is not much room. The second hard part is removing the fan etc. If you have a good pulley puller its not oo bad. So, if you are mechanically inclined and have worked on cars before then I would say go for it. If you cannot change the oil then don't go near it. Just go carefull and make sure you have lots of time so you are relaxed. If you get into trouble you can always post...we run a 27x7 shop on Rennlist!!

And I left the belt sensor on...I figured two insurance policies were good. Besides that Hans alternator was not charging the battery but he did not get a idiot light. His battery was new so maybe it could keep the charge up...its unclear why his light did not come on (yes, it comes on when the ignition was on) when the alternator failed.

Oh, and the alternator was about $300 Canandian + core charge fully rebuilt from Bosch supplied by Weissach.

Cheers,

Mike

JasonAndreas

If you spend time sitting in traffic then you really need to think twice before using the RS pulley. At the stock idle speed with the RS pulley the alternator does not turn fast enough to keep the system charged. Porsche's solution was to raise the idle speed to 1100rpm. It might not be a problem for most people but it is something you need to be aware of before trying this!

How much is the Porsche remanufactured alternator?

Edward

Jason is correct (of course ) about the RS alt as a potential problem for commuters. It really is not a good choice for those who use a/c, headlights, stereo, wipers ...gee, all the things I use on the road

As a "weekend" or pure "fun car," it's not an issue as you are not doing much idling (at about 650rpms). But regular commuting use can easily tax the charging system with the (slower) RS pulley installed.

Edward

MadMarkie

Hey James,

I have done the RS pulley update and R&Red the alternator on my car (and my previous RSA)... so if you decide to go DIY (and I think you should), let me know! It really is pretty simple, but I am available if you need a hand or get stuck. PM if you need my contact info. I used a rebuilt alternator in the RSA and had no issues for 4.5 years... so I will probably go the same route if the ever 993 needs one.

Cheers, Mark.

MadMarkie

Oh, and it's great to hear you are planning on driving at Arroyo Seco in September! The events out there are always a blast.