Sorry Guys - Sonic Boom in my Gen 2

I know it has been covered before with Gen 1 cars, but I have this in my Gen 2 Cayman. I have tried fiddling with the rubber knobs on the hatch, but no improvement. Obviously, I will take it to the dealer and see if they can do anything about, but I just wanted to check with you chaps - do you get used to it? Living in England, we have very poor road surfaces due to being run by a Communist Government - I don't think this helps!

I found it quite annoying when I first got the car, but I have mostly gotten used to it. I've fiddled with the plugs, but it just seems to come and go as it pleases.

What exactly was the problem? I am getting my Gen 2 Cayman soon and am anxious to know what are the potential problem. Thanks.

oh no, here we go again. :wall: Dont put up with it, get it fixed.

Tighten the latch which pulls the trunk lid down tighter. There is a good write-up in the article section. It takes five minutes.

Again, I apologies for bringing this up. So my Porsche Centre will know about this issue and be able to fix it? How come they don't set them up correctly at the factory? I am not going to start taking a brand new car to bits myself...!

Search for "trunk clunk" or "WM 537949". WM 537949 is a service bulletin done on Gen 1s with this issue. Dealer I purchased from did mine and 90% of the noise is gone. May not apply to Gen 2s.

Many thanks for your help, John :cheers:

Went back to dealer - they told me to give it a couple of weeks to see how I go.. Mentioned something about a counter weight?

I don't seem to have it on my Gen 2 (yet). But the rear hatch takes a good lean on it to shut.

What is it with the UK and poor roads? Does all of this stem from driving on the "correct" side of the road? Inquiring minds want to know!

We used to have very smooth roads, much better than the ones in Europe. We have now suffered 10 + years of a Labour Government who have not invested in our road network. Back to my car problem, I don't have any clunk noise, just this horrible buffeting, pounding sensation my ears, like pressure.

Nitrix - this still sounds exactly like what used to be called the trunk boom. Sometimes adjusting the bumpers helped but often tightening the latch was required. I had the same problem and moving the bumpers did nothing. Did you tighten the latch? You have to remove the plastic cover over the latch. loosen the two bolts holding it and move it down slightly so the back hatch is pulled down tighter.

That's exactly what my dealer does every so often to minimise the problem.

You might want to check the cabin exhaust vent to make sure that it is opening (don't know where it is).

I went to porsche shop yesterday, i have an 06 and mentioned about the trunk clunk fix. As mentioned by somebody else in this thread already-my tech told me that there is a harmonic balancer that they install "in" the rear hatch to over come the problem.It is a kit and that he would have to order me one.The fix is done under factory warranty at no cost to me and that it is what they are useing in the 09's to combate the problem.The only thing that i can relate this too is the "cocktail shakers" that where used in some of the older American convertable's that i have owned in the past.These harmonic shaker cans where used to overcome some of the structural integraty that was lost when you dropped the top-Cowel shake-.A bit of a band-aid fix to me and it appears to be something that is inherent in the cayman structural engineering design (or lack of) where the rear hatch is involved.Overall though it does not (obviously) effect the handling characteristics of the vehicle.I hope that my experience with this problem helps someone? I will post more when i go back to the dealer to have this device installed and hopefully i'll get a look at what exactly it is that they are going to do Just a thought i wonder if there is any adjustment in the harmonic device that can be done? I did not have an opportunity to ask yesterday as the service rep seemed a little vague also as to exactly what quality this thing has.

I just read my service report (imagine that), and it says this - Customer states thud noise when hitting bumps,check and advise. s101 verified customer concern,special order new rear hatch vibration damper kit 12250-Thump noise when driving over bumps.0.00 Test drove vehicle.Found thump noise coming from rear hatch area when driving over bumps.Found center weight for rear hatch moving excessivly.s/o repair kit including rubber buffers for rear hatch counter weight .End of service report. I know that this is a gen 2 post and mine is a gen 1 but when the service rep told me that this is what they are using in the gen 2's.I thought it may help

"You might want to check the cabin exhaust vent to make sure that it is opening (don't know where it is). " The vents are in the rear just in front of the tail lights. They are behind the rear hatch carpet where is comes up to cover the wheel well. However it is a one-way flap that lets air out but not in. Now that you mention this - this one-way air flow could be a root cause of the issue itself.

Many thanks to all you guys for the input on this thread. Your comments have been very helpful. I am going to leave it a week then phone up my dealer and book the car in for a day to take a look at the rear hatch. I also have a 'lumpy' tick over when idle which I want them to take a look at too. I really can't believe that Porsche couldn't have designed a fix for this with the Gen 2 car.

What could be Porsche's logic behind not fixing this for the Gen 2 car?

Update. Still not fixed. The latch is as tight as it can be. Even if I remove the bumpers, the hatch is closed solid. I think this harmonic thing in the boot is causing the problems. The inside of the cabin causes my ears to almost block up - really strange. I was hoping to get used to it but I have now covered 5,000 miles and it is no better. The dealer has taken in out several times as says there is nothing wrong with it. I love the look, the feel, the handling and sound of this car, but this problem is preventing me from bonding with the car - I don't know how much longer I can put up with this booming in my ears. I am really not very happy at all

I'll second that. Article is good and the hatch usually gets loose, especially if you tighten those side bumpers. The problem is that the latch is not secured very tight. I think maybe it's an error by the engineer...wrong torque specified...but there's no Loc-Tite on it either. Maybe they leave it loose for the dealers to adjust after shipping? Maybe the dealers didn't do that? Whatever the cause, the fix is easy. Loc-Tite the bolts and put them in tight with the lock all the way down. There is also a weight in the back door behind the trim below the rear window...That's another article. Both fixes help a lot. I still hear it but it's far less and doesn't sound "wrong" anymore. I have 19's. The noise seems to happen most when the right rear wheel hits bumps. After you fix these, do the Bose sub -woofer fix if you have Bose . Great!!!

The hatch can not be screwed down any tighter, believe me. There is no movement in the hatch even if I remove the rubber bumps completely. The funny thing is, it feels better with the rubber bumps removed completely. Before, you felt like you were underwater with this false sense of quiet. I don't understand the purpose of this weight bolted to the hatch that gives out the counter frequency. I don't like the idea of taking all the trim around the hatch off to fiddle with this, as I fear it will rattle when replaced/clips may break. The chap at Porsche said the Gen 2 have the fix on the weight which consisted of padding to stop the weights from moving. Anybody tried removing the weights completely? I think it is this false counter frequency that is messing with my ears. I never, ever thought I would have this sort of problem with a bloody car!!!!!!!!!!!!!!!!!!!!!

I have just removed the weight altogether, the boom is still there. My reason for removing the weight "after the dealers mod", was because it became useless and serves no function other than dead weight. You would like to think it still works but after rendering it 99% stationary,I just cant see how it can serve any function...:crazy: The wraping of the wieght only fixes the clunk & NOT the boom. After I have removed said damper the boom frequency has changed (ie. 19hz vs 23hz) so to speak. With that change, the weight of the hatch is 3lbs lighter overall, and the harmonics will be different as noted in the freq change. The only way I can think of completly removing the boom would be to either stop the hatch from moving completly, or find some way to create an isobaric chamber that would be 180deg. out of phase of the hatch. The thought of creating a tighter seal via adjusting the latch is something I will try in the near future, but I'm not expecting this to 100% cure the boom effect.

Glad to hear ul2fly reported on results with the weight removed. :thanks: I wanted to try that after I did my fix per the article but I had the car all buttoned up and didn't want to rip it apart again until I'd given it a good long test. I used self-stick black closed cell foam that was a bit thinner than the article calls for. I think mine was 3/8ths where the writer used 7/16". Not a big difference, but it allows a little more travel of the weight. The boom effect is still there on mine, but it's really a lot better. I thought tightening down the hatch helped as much if not more. What I don't get anymore is really loud booming on bigger bumps. What I still have is this low frequency thing on even small irregularities...and I'm sure it's not there at all with the front wheels and the right rear tire is doing it far more than the left rear. How does that make any sense? It's no longer intrusive and people who ride in the car really don't notice it, but I know that it's still there and I want it gone. I think driving this car would be a lot nicer if it were not an issue. The car is so tight and good except for this solitary bug. I'm almost thinking it's transferring from the bottom of the car rather than the top because of the difference between the two rear tires . Honestly, if I just hit something with the left rear tire, it doesn't happen. :crazy: As far as not wanting to remove the trim, I can't blame anyone. It was definitely a scary experience to pry on the back of that big expensive trim piece and when the first clip popped out, the sound made me jump! I've done a lot of maintenence work on a lot of German cars and bikes. Interior trim has always been intimidating for me, but the article was very good and descriptive. Once I got past the first couple clips, it got easier because I could put my hand in back of the panel feel the clipsand push them out with my hand. There was no problem with breaking any of the clips. They're metal except for the two on the window edges and those pull out easily. Just make sure it's lined up when you start putting it back in. There is an alignment pin in the middle just under the window and the metal latch hoop goes in its slot at the near side. I put the lid down to a more level position to do this and sat in a chair so I could see in under the liner. When it's lined up, you just hold the panel in position with one hand and pound away with your other hand starting near one of the two alignment points and the clips pop right in. Take a little extra care with the two plastic ones on the outside edges of the window and all will be well. :dance: I bought a small metal pry bar at the hardware store to get under the panel and pry the first few clips up. I put racer tape all over the pry bar to discourage scratching. I have since boutht that set of blue plastic interior tools. Looks like they will get a lot of use on this car. I can honestly say nothing broke or got misplaced. No extra parts after assembly and no bad effects from doing this. I don't think this fix completely solves it, but it's so much better. My latch was definitely too loose. One side of the lock had pulled itself out of position. I just put them both at the very bottom and tightened it up good with loc-tite. I think the latch made more difference than the weight. I put the side bumpers all whe way "in" and then adjusted them out just a littler to make everything really firm. It coudn't be any more solid of a fit without a stick welder. My guess is that it would still make the noise even if welded shut. Something is still missing in this puzzle. :wall:

Do you know what amazes me - not one road test in any UK magazines mentions it! Just goes to show, these hacks jump in a car, thrash it around, scribe, then go home for tea. Useless pratts

I've read a lot about this boom... and I still don't know exactly what it is... will this happen to every car? I have an 07, am I missing something?

I experienced the boom in my 2006 CS (18" wheels, no PASM ) and unfortunately noticed little improvement despite fully tightening the latch, adjusting the rubber bumpers both ways, and adding extra rubber to the bump stops. Rolling both windows down had the most effect. I ultimately ended up selling the car because of this -- my daily commute is on rough, frost-heaved roads and it became irritating (and sometimes painful) to drive the car. Admittedly, I think I have more sensitive ears than most but it bothered my wife as well. I was hoping that they would fix it for good with the gen II!

How did it effect your ears? Did it make them feel like they were blocking sometimes?

Is there a trick to adjusting the rubber bumpers? Mine won't turn in either direction. FWIW, I've had many 944's & they never had this problem.

On my really virginal '06 CS, the bolts that hold and adjust the rear latch (lower section, not the upper "hoop") were not very tight and were not loc-tited. One side was up near the extreme loose position while the other side was near the extreme tight position. This tells me that the lock moved. This is not hard to imagine as there is constant pressure on the latch from the lid pushing against the seal and the bumpers and all the vibration from constant banging of the tires against rough roads. I adjusted both sides all the way down and loc-tited them firmly down. In this setting, the bumpers are not critical. The door is tight on the seal. The noise is a lot more tolerable this way. I doubt that Porsche has addressed this noise one bit on the new Gen II cars....maybe just the padding on the conterweight. It is a bit of an accoustical nightmare, but it can be minimized without much trouble. There are many incredible positive aspects of the car, but it is not perfect and it is full of quirks. If you're looking for a "perfect" road car, look elsewhere. Porsche doesn't do "perfect". You will also be unhappy if you decide to ever track this car because there are a lot of weaknesses that need to be addressed. As a sporty car for two capable of quite amazing handling out of the box, it's pretty untouchable. If it's not for you, I'd advise dumping it while it's still new. I fear you'll take a giant hit on it in this economy, but you should get what you want. Just when I get ready to give up on mine, I go for a drive and savor the good stuff and I'm hooked again. -Six

Well the 85,000 miles I covered in my 2006 Boxster 987 were pretty perfect! I have now covered 6,000 in the Cayman since March and am finding the pain in my ears absolutely awful. I shall try another OPC to see if they have any solutions - if not, I will chop the thing in for another Boxster, which would be a shame , as I much prefer the looks and handling of the Cayman, but this pressure is such a major flaw in the car for me .

I have been driving my new Cayman S for two weeks now (18" wheels w/ PASM ). I am definitely experiencing the "boom" problem in which my ears have the sensation of pressure changes when driving over even minor bumps in the road. There is no audible "clunk" or "thunk" - just the sensation of pressure changes in my inner ear. It is very annoying and also makes my ears feel "blocked" for a while even after I have stopped driving the car. It is clearly a cabin pressurization problem because it goes away if I roll down a window an inch. What is the latest in terms of a solution for this problem? Does Porsche even acknowledge this is a problem? Unfortunately, as an engineer, I fear this may be a fundemantal design flaw and may not be fixable. In particular, I suspect that the pressurization is caused by flexing of the hatch due to the accelerations caused by driving over irregularities in the road surface. In short, the hatch is not stiff enough and the amount of flexing that occurs is enough to compress the air in the cabin. Messing around with weights and rubber bumpers is probably useless because they do nothing to affect the stiffness of the hatch. Changing the mass of the hatch with weights would affect the resonant frequency of the hatch - but I don't think this is a resonance problem. The boom is not that the hatch is vibrating, it is because the hatch is flexing and that is causing the air in the cabin to be compressed. I hope I am wrong.

Hello there, Check the gasket between third middle rear brake light and the rear windowscreen. Regards Christ

Can you please elaborate?

So what you want to do is go to the good dealer, show him the above and get it fixed. Don't put up with it. Don't trade the car. I did it myself because I hate wrestling with dealers over silly stuff like this. They seem to have limitless energy for not fixing problems and sending customers aways thinking there is something wrong with the driver. I recently found that the washer method of fixing this is more effective than the foam strips on the counterweight. Also, the latch on my car has two bolts, one was loose and the latch had moved all the way "up" on the loose side. Neither bolt had loc-tite on it. I put lock tite on and put the latch in the lowest (tightest) possible position on both sides. These fixes take 20 minutes at my garage. It takes 40 minutes one way to get to the dealer and then I gamble that I won't get in a frustrating tug of war with him. THAT is why there are car groups like this. I do the majority of the service work on my car because I know how it's done then and I learn something about cars every time. I agree in principal that your car SHOULD be perfect and the dealer SHOULD be perfect, but the fact is that the world is not fair. Sometimes we just have to accept that and get on with solving such problems. I think you have a lazy dealer. I thought we had an exclusive on these in the US. Guess not.

It's fixable. You are an engineer? You are not displaying much patience with this. There are many owners not experiencing this issue. I had it and got rid of it. Did it MYSELF. Many stories of people getting it successfully solved by the dealer though. I have more patience with cars than with dealers who don't listen.