[radonculous]

We recently picked up a 2018 Cayman GTS (CPO). The car has ~2200 miles on it and seems to be in excellent condition. We purchased it from a Porsche dealer across the country. Today is the first day I have actually driven the car for a lengthy period of time / distance and I noticed a rattling noise that sound like its coming from the passenger side vent area above 70MPH--albeit this rattling noise could be anywhere in the passenger side rear quarter. It sounds like what I would imagine a bunch of rocks sound like if they were bouncing around / stuck in the vent. When I look in the vent I see that its mostly covered and I can't see anything in there and there is no evidence of any damage. I looked under the car and also in the rear wheel well and can't see any issues or any debris. The performance / temps don't seem to be affected but the faster it goes over 70 MPH the more the noise becomes obvious. Its an unnerving noise and never had this noise in our 981S / GT4.

I read a few threads on this forum and did the diagnostics. I keep the passenger seat belt buckled so its not from there. Seat is forward so not rubbing. I even sat in the passenger seat and could hear the noise as coming from the vent / passenger rear quarter area.

Any recommendations?

 

[DocCayman]

Stone in the callipers? Turn wheel to the right, put your hand in and feel for it..maybe you might be lucky..same for the rear wheel.

 

[radonculous]

I'll check it out although no issues with braking at all...thank you

 

[MR69 ALB]

You May have the seat belt buckle tap tap tap rattle, make sure the plastic buckle is all the way to the top holding the insert off the back plastic bulk head.
my car suffered the same type of noise In the same area and i narrowed it down to this.

Hope you sort it soon

Cheers Andrew

 

[Naptown]

Does it change if there is a passenger in the seat?

 

[radonculous]

Hey guys no it still makes noise if someone is in the seat--rattling is not coming from in the cabin based upon my diagnostic with a buddy seems like its from the vent area but really there isn't anything I can see...hmm thinking dealer trip soon

 

[GTS18BGTS]

Hey guys no it still makes noise if someone is in the seat--rattling is not coming from in the cabin based upon my diagnostic with a buddy seems like its from the vent area but really there isn't anything I can see...hmm thinking dealer trip soon

Is it possible the side intake is not seated properly? They are plastic and clip into the recess. How about a stone inside the intake?

 

[Naptown]

Does it change with fan speed or if you direct the air to the floor or defrost. Could be something there. Is the cabin air filter loose?

 

[radonculous]

Hey guys thanks for the all the recs so far I have looked at almost every part of the interior and exterior everything seems securely fashioned--even put car on our lift and looked underneath looks fine. This is driving me nuts as its an issue about 70MPH (and gets more prevalent as you drive faster) and I am 100% its outside the cabin and 90% sure from the vent area...may take her to dealer soon...

 

[GTS18BGTS]

Hey guys thanks for the all the recs so far I have looked at almost every part of the interior and exterior everything seems securely fashioned--even put car on our lift and looked underneath looks fine. This is driving me nuts as its an issue about 70MPH (and gets more prevalent as you drive faster) and I am 100% its outside the cabin and 90% sure from the vent area...may take her to dealer soon...

Did you pull the intake trim off?

 

[johan]

Try to set the cabin temp to max/min and see if it changes anything.
If a vent tube have come loose you will do it better/worse with temp.

But i dont think thats the issue, as you decribe it there is something inside the vent

 

[Puffins_00]

Did you get it fixed? I'm having the same noise.

 

[PHB1969]

Loose gas strut on the frunk. Had something similar on a base cayman 2.0t

 

[radonculous]

@PHB1969 I'll also check that but noise appears like its coming from passenger vent or 3/4 region...

@Puffins_00 unfortunately the noise is still present. I liken it to some sort of buffetting in the vent...I was able to get the noise as low as 50mph and sometimes the noise is gone and comes back...I'll probably end up taking it to dealer