Strange noise
 

Okay, before you say "ask a mechanic," let me start out by saying that I'm on a trip with the car. The noise started today, about 60 miles from my home, noticed at highway speeds. It's intermittent, speed-related, and doesn't fit anything I can figure out. Not a chirp, more like a click or clunk. It SOUNDS like something is loose in the right rear wheel, or at least that quadrant. Sort of like a rock in a hubcap. Lug nuts were checked all around, all wheels feel same in temperature, center hub crests are tight, handling is fine. My drive here involved lots of twisties and hills, and the only thing I THINK I could figure was that it seemed to be louder, or at least more noticeable, was going uphill. I had the impression, not necessarily correct, that downshifting helped. At speeds about 20 mph I hear a distinct noise, but as the speed increases, the noise becomes more like a steady tone, if you can understand what I mean. In other words, speed related. Tires look okay. Slipping the car in neutral doesn't stop the noise, which I think is important.

Every time I think I'm on to a pattern, or have someone else drive it (hubby, for example), the noise stops. We are in 2 cars, and we switched out for a while, with no luck. He could hear it, though, when I drove by him as he stood by the roadside. Also he heard it briefly when he drove it. He's stumped, too.

The car is up to date on maintenance, had new shifter cables installed a couple of weeks ago (and is shifting fine). Earlier in the fall my mechanic thought I needed a new motor mount, but when I brought it in for the cables, he said he didn't think so after all.

So--what should I do to troubleshoot? What information should I try to gather? 2002 986 S 6 speed, 85,000 miles.

You know we're guessing.... but....
I'd check the CV joint on that side.


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How can I check it? Again, I'm on a trip, so not with my usual people/equipment.

A quick read on Google revealed that accelerating while turning would make it sound worse. I couldn't hear any difference when cornering. First noticed this noise on a straight section of road at a steady speed, in fact.

^^ I agree. ^^

Reach under the car, grab the drive shaft near the wheel, and try to yank it around a bit. If it moves, clanks, or feels loose, there's your problem. Do the same check with your hand on the transmission side of the drive shaft.

The good news (if there is any good news) is that things like this rarely get better on their own and as they get worse, it becomes easier to diagnose them.

Also, make sure that the parking brake is fully disengaged.

Okay, thanks, guys/gals. We'll check that in the morning.

That applies to front wheel drive cars.

That's true of a front wheel drive car. The idea being that as the joint is flexed in both directions (up / down, left/ right) , it'll make more noise. But on the boxster, being rear wheel drive, it only flexes on the one axis regardless of any turning. So no additional noise from turning.


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Clicks and clunks are generally a sign of a CV, so I’m with the rest. If it is rythmic it could be a wheel bearing, but my $ is on the CV.

Okay, we found a lift in the town where we're staying. Hubby says there's a little play in the axle. CV boots are dry, no grease leaking anywhere. The mechanic who went under the car with him (albeit not a Porsche mechanic) said he didn't think it was CV joints. They went on a test drive but couldn't duplicate the sound. The car wasn't warmed up, though, and every time we really hear it, the car has been run for about 50 miles. Stopped for lunch and didn't hear anything until it was warm again. It's been in the 40s and 50s here (47° right now).

Does this change anyone's thoughts?

Might be best to try to find a Porsche guy or dealer somewhere amongst your travels to get a good diagnosis. Really difficult to do over the internet. Having said that, I still think it’s CV related. There just isn’t much else in that area to “rattle”. There is another possibility and that is a rattling catalytic converter. It would only make noise (generally) when hot...

Also, just reread your post regarding the engine mount... with your year and mileage I can pretty much guarantee your motor mount is shot if it is original. My 02 had 55k on it and my MM literally fell out of the carrier when I changed it. It is very common and not to hard/expensive to replace with a newer 987 unit.

Well, I know you're all sitting on pins and needles waiting for the diagnosis, and here it is: Mudflaps! Seriously, while we were on our trip (to Porsche Palooza in Eureka Springs, AR), we noticed that the bottom edge of the flap on each side was partially torn. With the wind, it was flapping. Hubby taped each side to see if it made a difference before we headed home, which was just under 200 miles away. Didn't hear the sound until about half-way (groan). When we stopped for lunch, we saw that the tape had pulled off. So, empirically, that's the cause. We're still going to run it over to our P-car mechanic when we get a chance. We also found that the tires need balancing, but that wasn't related--vibration, not noise.

Dang flaps! Need to update them to the new 'Solution flaps'.

So....part 2 of this saga. Yes, we thought it was the flaps. Yes, we drove the car home with no problem. Yes, everything was fine for nearly 1000 miles, not even noisy. Then today, Thanksgiving Day, we drove down to a state park about 50 miles away. No problems getting there. On the way home, something changed. We now have the worst sound that we've heard, again right rear, a real click/clunk/tap sound, speed dependent. We limped home. So, I guess we go back to CV joints after all. New questions:

1. Obviously it needs to go to the mechanic, who is 50 miles away, mostly 2-lane highway and interstate. Drive or flatbed?
2. What happens if Something Bad happens on the way and it totally fails?
3. What are the warning sounds/events before this happens?
4. Is this a DIY job for the average guy who restored a 356, does brake jobs, changes oil?

No comments? I'm probably going to flatbed to my indy Porsche mechanic on Monday, but still would like answers to my questions.

I think you threw us all for a loop with the "on- again, off- again" nature.

Here's your questions, with my own shot at them:

1. Obviously it needs to go to the mechanic, who is 50 miles away, mostly 2-lane highway and interstate. Drive or flatbed? (I'd flatbed it, if that's an option)

2. What happens if Something Bad happens on the way and it totally fails? (Exactly why I'd flatbed it. Because we don't know what it is, we can't guess what'll be damaged if it fails catastrophically)

3. What are the warning sounds/events before this happens? (The "BEEP-BEEP-BEEP" of the flatbed backing into the drive)

4. Is this a DIY job for the average guy who restored a 356, does brake jobs, changes oil? (Typically I'd say Yes... if it's indeed CV- related. But the problem here, is that if you don't know how to inspect the CV's, then no, you shouldn't be replacing them. I'm not trying to be rude here.... but I will ask: how does a person who can't differentiate between mud flaps and CV joint noises, "restore" a 356?)


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maytag, you have some interesting comments. I think the main thing to remember is that this was always an intermittent noise, as stated before, UNTIL Thursday. We were both in the car then, and we started hearing the noise again, but as we rolled on, the sound changed. It became more...mechanical. It's really hard to describe noises--you have to hear them--but there was a bit of a metallic element that hadn't been appreciated before. Also, from a standing start, there was an additional creak/groan noise.

I've been in contact with my mechanic, who has given me the name of the flatbed company he uses. After talking with him, no way will I try to drive. The first 20 miles is 2-lane, totally rural, and the remaining interstate is busy, crowded, and not conducive to breakdowns.

As for my DIY question. Remember, we had this car up on a rack, and both spouse and the garage owner said it didn't appear to be CV joint related. You ask how someone can restore a 356 if you can't differentiate between CV joints and mudflaps. Again, remember that the sound was intermittent. When spouse and the garage owner went for a test drive, they couldn't reproduce it. When another friend went for a test drive--someone who owns 7 Porsches of various types and vintages--he came back saying it was "a really tight car." He didn't hear it. Something has since broken for good. Something changed. Perhaps there were 2 issues--after all, taping up the mud flap worked for a while until the tape came loose.

Ever look at a 356 engine? It's a whole lot simpler than a Boxster's. It wasn't hard to overhaul. All of the mechanical work, plus the interior and more was done right in our own garage about 17-18 years ago. We farmed out the paint and rust repair. I'm the first one to say 356s aren't glorified VWs, but the fact is they're a much more...fundamental...car than a Boxster or 911. Many a hippie has kept a Bug running with little more than bailing wire and hope, including some of my friends. He did restore the 356 (no need to use quote marks). I was there and I helped. We've owned that car for 51 years. He continues to do a lot of the work on our other cars, and the question is how far can he go on this one, and how much does he want to bother? Here's a photo of the 356, and the Boxster in question.http://986forum.com/forums/uploads02...1543184664.jpg

::sigh::
Whatev'....

You pushed, and were uptight about nobody responding..... so I responded.

It has now become clear that the individual who can DIY, and the one who can restore a 356, and the one who may be able to troubleshoot this sound, and the individual who is likely qualified to replace CV's, is not the same individual who is posting here about CV's, mud-flaps, tape and sounds that you can't explain, which must be heard, but you require an opinion of us anyway.

So..... yeah.
::sigh::


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I'm the one who's been posting about all the symptoms and sounds, but I never said I was the one who works on our cars, including the 356 restoration. You know what they say when you assume...