Surf Twang

I just returned from a week away and took my RS America for a drive. It immediately started to sound different and then there was a loud bang and all the warning lights went off. I immediately pulled over and turned the engine off. When I looked into the engine bay I saw the fan laying there totally free with a broken belt.

I just had the 60k service done 1,100 miles ago. Among other things they replaced the belts as well as the distributor caps and rotors. My question is: how common is it for the fan to break off like it did? Do you think they could they have done something wrong during the 60k service that contributed to this?

Thanks.
David

Ade - C4 91

Hi David,

Check for damaged thread, but I'd say they forgot to tighten the fan nut.

Ade.

Surf Twang

Thanks, Ade. The car has been towed to the repair shop so I can't look at it but if the fan is bolted on then I think the bolt broke.

Adrian

Dear Surf Twang,
Yours is the first I recall where the fan has actually broken off or come off. I would say the fan broke the belt. Do you have the normal belt set up or has your RSA been converted to the one belt driving both fan and alternator.
Is the bearing still in the fan hub?
I agree with ADE that they must have undone something and forgotten to tighten it up. However please check exactly why the fan came off because this is something new and does require more investigation.
I wonder if the nut was overtorqued or the belt was so tight it caused the fan to run out of true.
Ciao,
Adrian
911C4

Surf Twang

Adrian, my RSA has the normal belt setup. I think you're right about the fan breaking the belt. I won't have an idea why the fan came off until Monday. Stay tuned and thanks for your help.

By the way, what part of Switzerland do you live in? I used to travel to Zug on business four times a year.

David

Adrian

Dear David,
I live in the village of Walzenhuasen. It is in the very top of the North East of Switzerland right on the border with Austria. It overlooks the Bodensee (Lake of Konstanz). I can see the Austrian city of Bregenz from my balcony. The border is about 2 km away straight down.
Ciao,
Adrian
911C4

Syd B.

If the alternator were to seize, could this contribute to the broken belt?

Adrian

Yep,
Ciao,
Adrian
911C4

Surf Twang

I'm also beginning to think seized alternator. Immediately after the 60k service I noticed a high pitched whining noise that I didn't pay much attention to because the Ferrari's I owned in the past also made this kind of noise. Looking back it may have been a sign that the alternator bearings were going bad. In my opinion, the repair shop should have noticed this during the test drive.

I should get the verdict tomorrow. Thanks everyone for your replies.

David

Surf Twang

Well, the bolt that runs through the alternator sheered off where the alternator and the fan meet. The alternator did not seize and in fact still turns.

The repair shop claims to never have seen this before and maintain that it was not caused by anything they did during the 60K service. They suspect metal fatigue. At this point I have no evidence to prove otherwise.

Surf Twang

On mine it was not the fan bolts that came adrift but the solid steel shaft that runs through the alternator. It must be about 3/4" thick and it just broke in two right where the fan attaches to the alternator.

chris walrod

I wonder if this shop shimmed the belt(s) way too tight causing this?

I hate the 'coinsidental' things in life....HHMMMM

Surf Twang

The shop claims that tight belts wouldn't be able to break a 3/4" solid steel shaft. I can't prove otherwise so I guess I'm stuck.

Christer

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by chris walrod:
<strong>I wonder if this shop shimmed the belt(s) way too tight causing this?

I hate the 'coinsidental' things in life....HHMMMM</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">What is a 2000 Prerunner?

Syd B.

If a 3/4" steel shaft can break in half from metal fatigue on a 12 year old car, then I'll be less enthused the next time I step onto a 20 year old Boeing 727. I find it hard to believe that a metal shaft could fail like this unless there was some extreme and abnormal force at play. I agree that over tightened belts would be an unlikely culprit, however, the fact that a belt was also broken in this situation is interesting. Could you tell from the condition of the broken belt if it was sheared by the fan or if it broke separately? If it appears to be the latter, could a seizing alternator have caused both. If your alternator bearings start to fail, it will not necessarily happen at once. It may partially seize and then operate again for a short time. Did you hear a whining noise before all of this happened? Let us know once your mystery has been resolved.