GT4 interior rattle in the rear - Page 1 - Boxster/Cayman - PistonHeads UK

Hi guys, took my GT4 on its first long motorway journey today and it was a great experience bar a strange rattle I could hear in the rear of the cabin when going over 70mph. It was constant and the faster I went, the more prominent and consistent it became. It’s not super loud but once you hear it, you can’t ignore it. Has anyone else noticed this with their GT4? It’s not the passenger seatbelt issue as I had my partner in the car with me.

Bit difficult to pinpoint without a more detailed description… Where did it sound like it was coming from? What kind of sound? Plastic tapping, metal on metal? One thing to check is the rest boot privacy cover… make sure that done up properly… Also the rear boot lid rubber feet… make sure they are adjusted to a good position to engage the body. Also, it could well still be the ‘seat belt area’ issue, as a number of the sounds potentially coming from there have nothing to do with the seat belt itself. Edited by TDT on Sunday 9th April 18:58

TDT said: Bit difficult to pinpoint without a more detailed description… Where did it sound like it was coming from? What kind of sound? Plastic tapping, metal on metal? One thing to check is the rest boot privacy cover… make sure that done up properly… Also the rear boot lid rubber feet… make sure they are adjusted to a good position to engage the body. Also, it could well still be the ‘seat belt area’ issue, as a number of the sounds potentially coming from there have nothing to do with the seat belt itself. Edited by TDT on Sunday 9th April 18:58 Hi mate, the sound is definitely coming from the rear. My partner was the one who first heard it and we both kept looking behind trying to work out what it could be. Definitely sounds like plastic tapping as opposed to metal on metal. It’s fairly faint but constant when doing over 70mph. Gets louder when hitting higher speeds. We had low volume music on during the drive but could still hear it. I really don’t think it’s a seatbelt issue as the sound was coming straight from the rear. At one point I was thinking is the spoiler loose haha. Regarding the boot privacy cover, what exactly am I looking for here? The boot lid rubber feet do swivel to the right and left very easily but I wouldn’t say they feel like they’re fitted loosely. Is this normal?

Tighten the boot privacy screen screws - two large adjusters visible when you open the boot. My money is on it being the plastic part in the video TDT posted. I had it in my car, double sided foam tape solved it.

Great insight guys. Mine has exactly the same rattle from the just behind the passengers head. Sounds like a seatbelt mechanism tensioner - quite tinny and high(ish) frequency, as annoying as hell - above 40mph on nearly all UK road surfaces (i.e. crap) but when you hear the poster rattle that plastic bit in the video - that’s exactly what it sounds like. Will attend to this shortly… :-))

It's a very easy fix. Take your time and use a trim tool to pry up the parts. Use as wide a tool as possible to spread the load and not damage the plastic

Twinfan said: It's a very easy fix. Take your time and use a trim tool to pry up the parts. Use as wide a tool as possible to spread the load and not damage the plastic Yes! It certainly is a very easy AND super satisfying fix. I see that Porsche fit a rubber ‘end piece’ at the end of the ‘tang’ - so over time, this little rubber stop - falls off - as it vibrates… One side was missing, and the other side on mine was still ‘on’ that black tang - as pointed out by the other video poster. I used some spongy weight lifters - sticky ‘finger tape’ - gently lifted up the tang, and put 2x wraps of tape under the vibrating - tapping - chirping end… boom! Test drive above 30 mph (which is when the chirping started’ all gone… just the chuffing and chunting of that 4.0 behind my ear now… thanks for the steer and the fix - brill. Best thing was not having to take it back to the dealer… My fix materials attached: (removed clear plastic bungs & the two ‘soon to fall off again’ rubber bungs…)

Glad you're sorted! I don't remember seeing the black rubber bungs on either side of my car, so they may never have been fitted from factory, but I had the clear ones though. Where do they fall, right to the bottom of the trim under the seat belt? If so I guess I'll leave them there! Mine is an early 2020 car which may make a difference.

Twinfan said: It's a very easy fix. Take your time and use a trim tool to pry up the parts. Use as wide a tool as possible to spread the load and not damage the plastic Also good advice for the original poster - take your time, just go at it very gently, gingerly, no rush - don’t overly force the plastic covers (mine has the roll cage too - which is a bit fiddly) it is all pretty intuitive - and utterly obvious which part is doing the rattling… :-)) Just put in a full tank of optimax - the new golden valley stretch between Cheltenham and Gloucester is billiard table smooth & the new ‘middle’ roundabout near Innsworth - wide, smooth, great visibility - I had a few go arounds! Then shuffled away before any boys in blue might have been passing… What a machine… :-))

Twinfan said: Glad you're sorted! I don't remember seeing the black rubber bungs on either side of my car, so they may never have been fitted from factory, but I had the clear ones though. Where do they fall, right to the bottom of the trim under the seat belt? If so I guess I'll leave them there! Mine is an early 2020 car which may make a difference. Mine is mid ‘20. The passenger side (black rubber end piece) was off and just bobbling around near the aluminium cross brace. The drivers side was ‘on’ it just kind of ‘pushes’ on to the end of the black plastic - long thin vibraty tang that sticks forward and ever so slightly ‘L’ bends downwards - towards the floor, just around the aluminium section. It would be obvious that any vibration would see that little rubber hector fall off. Mines just clicked 11k - so probably rubber fall off mileage reached?

DallySingh said: Hi mate, the sound is definitely coming from the rear. My partner was the one who first heard it and we both kept looking behind trying to work out what it could be. Definitely sounds like plastic tapping as opposed to metal on metal. It’s fairly faint but constant when doing over 70mph. Gets louder when hitting higher speeds. We had low volume music on during the drive but could still hear it. I really don’t think it’s a seatbelt issue as the sound was coming straight from the rear. At one point I was thinking is the spoiler loose haha. Regarding the boot privacy cover, what exactly am I looking for here? The boot lid rubber feet do swivel to the right and left very easily but I wouldn’t say they feel like they’re fitted loosely. Is this normal? We get the same on my wife's 2018 BGTS. Have made sure the cover under the softop if secured...it is now! But on saturday I noticed that the air intake "inserts" they added as a factory recall to stop cig ends going into the engine, are only clipped in. On the drivers side, it was deffo loose (passenger side was good and snug). I pulled on the little tab that is there to aid fitting and it made a clunk and now seems to have slotted in. Confession: no idea if this has fixed it as havent used it since. But you are spot on...only above 65-70mph and rattles more or less with road surface bumps and it sounds like plastic against plastic right behind the drivers seat. Have a peek at yours, may be the same.

Twinair said: Mine is mid ‘20. The passenger side (black rubber end piece) was off and just bobbling around near the aluminium cross brace. The drivers side was ‘on’ it just kind of ‘pushes’ on to the end of the black plastic - long thin vibraty tang that sticks forward and ever so slightly ‘L’ bends downwards - towards the floor, just around the aluminium section. It would be obvious that any vibration would see that little rubber hector fall off. Mines just clicked 11k - so probably rubber fall off mileage reached? Cheers, I couldn't see the end piece in the video above when viewed on my phone unless I missed it? My car rattled from new so I suspect it may never have had them...

Sadly the theory about the intake cover...nope...not that! But she did say the rattle stopped when she had put a heavy bag in the boot on the driver's side. Strange! May need to get OPC to investigate.