About half the time I start my 1993 968, there's a loud screeching sound that is exactly like a belt is slipping. The screeching lasts for about 30 seconds, reaching a crescendo and cutting off like someone flips a switch. Both belts (power steering and alternator/air conditioning) are good and snug. It's not related to the A/C, because it will screech with the A/C off.

Today, I was driving the car while it was doing its 30-second screech, and the screech got really loud and cut off. When it cut off, I could feel a distinct increase in power from the engine, as though whatever was screeching was loading the engine. Since I've ruled out the A/C, I figure that there's a problem with either the alternator, power steering pump or water pump. (The water pump is driven off the back of the timing belt.) Everything seems to work okay while the car is screeching -- there are no dash warning lights for a weak alternator and the steering feels fine. I can run the A/C or not run it, and it doesn't affect the screeching.

I have a few ideas about how to troubleshoot this but wonder if someone out there has experienced the same thing and can point me toward the problem. Thanks!

Bob Kovacs

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Ken, I don't have a gauge to determine the exact belt tightness and am just going by experience. Hadn't thought about a rebuild... since I don't use the car much, it can sit for a couple weeks waiting on a rebuild. Thanks for the tip!

Bob Kovacs
I went ahead and got a new (actually rebuilt) alternator for the car. I installed it this morning and so far everything is running fine. No hint of a screech yet. I got the alternator at a local autoparts store for about $150. There was an $89 core charge, but I just got that back today when I returned to old alternator. I thought $150 was pretty reasonable.

I checked the voltage with the engine running and the new alternator is putting out about 14.6 Volts. The old alternator was putting out about 13.5 Volts, which I thought was a little low. The first benefit of higher running voltage is that the dash lights are noticeably brighter -- still not what I'd call bright but definitely brighter than they used to be.

BTW, it's something of a bitch to replace the alternator in the 968. I had to take the bottom cover off the engine to get at the lower bolt on the alternator. Then the alternator is removed from the top of the engine. I just hate taking the under-engine cover off... that's always a pain to deal with.

I'll let people know if the screech returns, but so far so good.

Bob Kovacs
That sure sounded familiar. Good work. Where did you go for the alternator?

My next job is the Compressor for the A/C.
Excellent, hope it sticks (the fix, that is). By the way, since I am new, could you guys point me toward the most accessible shop manual? Is there one online or downloadable? (if that is a word, spell check says no).

I will want to do similar work in the near future.

Oh, and my "doh" moment came shortly after I got my car home: It does not have the lower engine protective plates/cover. None of it! Sure, it make it easier to work on, but also exposes the sensitive bits. Nice return for the PPI I paid for, eh? This was from Inter-Shop in Wilmington, NC in case you are wondering, and they had worked on the car for nearly 2 years, including replacing the TB and WP, and new brakes in the last year.
I can easily see where a mechanic would leave that %$^#% lower engine cover off, because it's a pain to constantly take off and reinstall. Still, it's best to have it on.

As for the replacement alternator, I bought it at a local Autozone store. Several local parts stores showed a remanufactured replacement for $135 to $160, so I just picked a store and bought it there. None of the stores had it in stock but it arrived in a couple of days after the order.

I replaced the alternator in my Subaru a few months ago and it was physically smaller and lighter than the 968's alternator. I would think that a smaller, less-beefy replacement alternator for the 968 could save 10 pounds, if that's your thing.

Bob Kovacs
You can find pdf versions on ebay for a very good
price. Make sure they include the 944 manual also.

found this one, but I do not see the 944 as a separate section.
That's the one I have. When I bought mine off of eBay, the seller included the 944 FSM for it so that many of the things not included in the 968 manual were also covered. That's a great website! All of the appropriate manuals are here: www.cannell.co.uk/manuals.htm


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