racngrn

Winter is coming soon and I took advantage of the last real opportunity for a ride in my 84 Carrera. Loves the cool weather. After about an hour of driving, I stopped to visit folks and when I started the car to leave, I noticed a rather pronounced rap/knock that was sensitive to rpm but not speed. Almost seemed like what a fan bearing might sound like ( thinking back to my VW days)?? No noise at idle, but just off idle you heard it. Oil pressure fine, oil level fine. Not a rap like one would hear from a rod , etc.. but more "exterior " than that. Car ran fine and strong. About 15 minutes into the return the noise suddenly stopped and did not return, even after repeated shut downs and re-starts. Thought it may be a vibration ( some loose component), perhaps exhaust related, but can't help but think it was more bearing related. Any thoughts? Assuming there is a bearing on the fan, could the noise suddenly appear and disappear? Hate these noises that come and go. Would rather have it there so it could get addressed during the winter storage. Appreciate your thoughts.

Reiver

Fan blade hitting the surround? Check for scrape marks...some of the old mag housings can flex quite a bit at times.

racngrn

Thanks. I did check that after reading some older posts. All good. I ran the car again last eve and no noise, but did see some smoke coming from a connection at the heat exchanger ?? ( right side of the car towards the back (transaxle) end of the motor. Wondering now if an exhaust leak may have developed and started as a noisy failing gasket. Not sure. Car gets stored with my mechanic, so plenty f winter months to sort it out. Thanks for the help.

ricster

good time for a tear down over the winter

racngrn

Yikes!! hope not. 55,000 miles and runs really strong. Started it again tonite and no noise. I hate to be an "out of site ( or sound) , out of mind guy, but could have been a freak thing. Mechanic is awesome, so he'll have some thoughts. Overall, hate to see it go into hibernation. Hate winter more and more each year.

Reiver

I had the fan issue that lasted exactly 20 seconds and stopped. Sounded like your experience as it's pretty damn loud and rpm specific..Is your fan housing in good shape as that Mag casing can really degrade if not properly protected and it will flex and pull down into the fan if it is losing its integrity and the belt a tad too tight.... have you messed with the fan belt at all?

racngrn

Fan housing looks good. I checked the inner surface for any evidence of scoring, didn't see any. I haven't messed with the belt either. Kinda hoping it comes back so I can further diagnose the problem. Thanks for the help though.

dhc3

Chain tensioner?

racngrn

Possibly, though I would expect more of a metallic sound from that . Started it up a few minutes ago and still quiet. I get obsessed with this sort of thing, but may just need to let the pros take a peek before worrying too much more. The motor is nice and quiet now and that gives me confidence it is quite likely not anything catastrophic or internal. Also wondering if it may even be part of the rotating mass in the trans. That is also behaving normal, but plenty to lose sleep over. Thanks for the continued interest and help.

upier

Reminds me of the adage that any problem that goes away by itself tends to come back by itself.

racngrn

Yes, sometimes with a friend or two! Being a preventive maint type of guy, this is hell!

porsche930dude

Crazy things like that happen to me quite often since I dont drive the car very often any more. Last winter It was literaly pouring oil out behind the cam box when i started it up. I said screw it im taking it around the block one more time before i have to fix it. Got home and no more leak. Fixed itself But yeah id say maybe a chain tensioner got stuck or something. Cant fix what aint broke

Derek911

If it ain't broke don't fix it. There is a difference between symptoms and illnesses. You will see symptoms first before the illness becomes obvious. Just add this to the symptoms list and eventually an illness will be diagnosed. Ideally symptoms lead to prevention, but sometimes the symptoms are so vague that we need more symptoms or a full blown illness to lead us to a remedy.

racngrn

Good advice all around. This is a car that was sparingly used through its life and still retains most of its original parts. I don't drive it that much either, but I am trying to wake her up a bit when I do, appreciating that these motors do enjoy ( maybe even need) some higher RPM time. I store and maintain the car with a true Porsche enthusiast and technician in Dover , NH ( Talbot Motors) and he will find this gremlin if anyone can. Really appreciate the advice.

theiceman

this sounds quite catastrophic to me .... il give you a chance now to sell it to me dirt cheap and i will tak eon the cost of the entire rebuild if it needs it ..

relax ... youl be fine .. .