jumper5836

I test drove a car with 184k km on it. When I accelerate it clunked from the rear and clunked as well during regular up shifts. It clattered all over bumps.

I am just wondering if the clunk is suspension related or engine mounts or maybe drive drive play. Actually the clutch engagement point was an inch from the floor so I do know that the clutch is worn but I don't believe a worn clutch would make a clunk sound.

The car is not lowered but it has seen a lot of driving. How long does the suspension usually last for?

Macster

Suspension service life is like tire life, clutch life, fuel economy, oil consumption, etc. it depends upon the driver, where the car spends it time if it gets driven in bad weather and even snow/ice and on salted/gritted roads, how the car is driven.

Some techs have told me the struts need to be replaced after 60K miles. Others tell me to not bother if the struts are not leaking and the car feels stable and doesn't bob/weave or pogo down going down the street. When I hit a dip at speed the car reacts of course but doesn't keep up the porpoising action that cars with bad shocks are wont to do.

The 996 is a bit too stiffly sprung I think to do a bounce test. I can do the bounce test with my less stiffly sprung Boxster and the front and rear ends of the car continue to move up and down a bit longer than I recall when I did this years ago when the car was new. But the struts are not leaking and the tech said to leave them alone. I might add tire wear is even and the car retains its alignment over more 6 new tires which works out to 40+K miles. How the math works: Starting with new tires all around then after 20+K miles the rears get replaced. After another 20+K miles the rears are due to be replaced and then I replace the fronts which have 40+K miles on them.

Noise during accel/braking may be related to bad engine or transmission mounts or a bad dual mass flywheel.

Another test for a bad FW is when you move the car off from a stop if the clutch engages smoothly with no clunking noises. A grabby clutch can also be a worn clutch, but shouldn't make any clunking noises.

If the clutch engages fully just an inch from the floor that is a much lower engagement point that I can ever remember when my cars' clutches were brand new.

That casts suspicion on the clutch's installation and thus the clunking could come from the clutch proper.

Clattering over bumps can be due to sway bar linkage wear or breakage.

I watched a tech inspect a car the other day that a customer brought in with a makes noises on the road complaint and the tech lifted the car in the air and used a nice pry bar to try to move suspension/steering/drivetrain components around to see if any had any play or felt like they were making contact with metal vs. rubber.

So if you can arrange to get the car in the air you can do the same or better yet have your favorite mechanic do this for you.

Or you can just redo the suspension. After adjustable links, aftermarket bushings, new OE or after market struts, springs: The sky is the limit. And so is the cost.

Sincerely,

Macster.

jumper5836

Thanks, much appreciated.

awrryan

If you're thinking of buying it and you need a mechanic to do the work, I would probably pass. The parts and labor add up fast for what you're describing and it my pay to buy a lower mileage well-sorted car rather than one that you know will cost you and arm and a leg.

jumper5836

Well I am figuring out the price delta and the end of the day. Before paying my mechanic to confirm what I all ready know. I'll pre-quailify it prior to wasting his time and my money. I am not looking for a perfect car just a good winter beater and I can take as much as 5k hit prior to it being recyled, I'd rather only take 2 or 3. That's the price you pay to drive a Porsche.

Macster

Just a few more comments. If the car is not yet yours the reasons for the clunking needs to be determined. It may be something relatively minor but it may be the signs of a car that has been seriously thrashed or bent and badly repaired.

If the noise is not determined to be the result of a beat up car, badly repaired car, just normal suspension wear/tear that's ok.

If the car is just going to be a winter car you can let some things go as long as -- and this is important -- the car is safe, stable to drive.

Remember too though that what passes for safe, stable on dry warm roads may not be the same when on wet, icy, cold roads. If the tires are not kept in contact with road surface in marginal traction conditions this can result in a more dangerous car to drive in marginal traction conditions and a car not worth - imho -- the risk.

If I haven't already mentioned it my 02 Boxster is on its orignal suspension with now over 260+K miles. The 911 is a heavier car a more powerful car so 260K mles may not be realistic for the 911 on its OE suspension but the suspension can last a long time.

Sincerely,

Macster.

jumper5836

It's actually a 986 S. Posting here, since really this is just a common sense question and I have been on the board long enough to know the 996 section is one of the better sections to get common sense questions answered. The cars are very similar aged. As well as having the clunk sound it almost lurges under aceleration and when you suddly lift it's like the front or rear dips and bobs.

I believe it could be the clutch and possibly the fly wheel and not the suspension but just worn bushings.

ltusler

Lurges?

Lunges or lurches or both?

jumper5836

single lunge like something just grabbed or like the brake was stuck on and just let go. I've tested low speed full throttle from 3rd and 4th gear and their was no slipping. I found 2 other cars that drive fine. Clutch was just done on one car and engages very high at least half way up the pedal travel and the other is more worn but engages lower but still 1/3 up.

Macster

If the car pitches up or down under acceleration or braking or bobs up and down over roller coaster road sufaces, if the rear tires (or even the front tires) skip/skitter in a sharp turn on rippled pavement the car's suspension is highly suspect.

(I do not consider the front tires the inside one at any rate that skips when making a slow sharp turn generally when backing out of a tight parking place a sign of anything wrong in the suspension/steering systems.)

Now the clunking or dramatic lurching/lunging you mention could be clutch related or flywheel related or even -- and these must be seriosly considered -- motor/transmission mounts. I believe these as possibilities have been mentioned before.

My experience with my Porsches (and other high performance cars with suspensions to match) is they do not raise the nose in the air nor drop it down a worrisome amount when things are working ok.

Now I do realize that in a very hard braking event will have the nose drop and right now but the times I've had to do this the car has not even made one hair stand up on the back of my next.

And those times I have really nailed the throttle on the Turbo the front end comes up and the rear end squats but again the car's behavior never once has me thinking it is not behaving perfectly normal. The car has lots of hp and torque and real good rear wheel grip and AWD too boot. All the engine's hp/torque goes to moving the car off the line and down the road and the body reacts as one expects it should.

In fact I believe I could if I wanted to experiment get the Turbo's nose airborne on a few sections of roads around my area -- well, in the nearby mountains -- that have an steep uphill gradient with a nice sharp road crest and with a massive amount of throttle.

Even so I understand the dynamics involved and would not worry about the suspension at all.

(Well, I would worry about the front suspension's landing which is one reason why I have not done this with the Turbo.)

Get your car in the air and get the suspension and engine/tranny mounts looked at.

If anything amiss is found have it fixed then see of the clunking, lurching, et all symptoms are gone. The clunking could still be present for it might be due to a failing flywheel.

Sincerely,

Macster.

jumper5836

Exactly what I was thinking. I am not talking braking but just lifting. The car does not feel like it has more power then a regular 986S, honestly I would think it felt slightly less powered then others I've driven. I've been in 996 Turbos and they will bob up and down because of the torque but with a 986S were talking 1/2 the torque if that. Even my C4S will squat under acel but it doesn't bob, it squats and lay down instantly not slow and awkwardly dramatic.

Macster

Working from memory (always risky for me) the Boxster S has a bit more than half the torque of a 996 Turbo.

The Boxster is more softly sprung too, arising from it being a roadster.

Even though it is a mid-engine configuration the Boxster has a substantial rear weight bias very close the same as the 911, especially including the AWD models.

The AWD models have additional weight at the front of the car while their engine is not that much heavier than the Boxster engine.

If the car was driven hard on poor roads (which is just about every road nowadays) the suspension could just be tired and this goes along with the rest of the car, the engine anyhow if it is truely down on power compared to other Boxster S models you have driven.

There are differences between similar used cars which is why it is so important to drive one before buying the car.

Sincerely,

Macster.