SilverFrog

Hello guys!

I have a weird noise on my 997.2 (another one ). It's like a chirp/rattle noise on driver side that only appears once the car is warmed up and ONLY on low revs, approx 1100 rpm and is more pronounced when moving from a dead stop. The noise can't be heared if we give revs as the car is still. This is driving me crazy, I thought it was related to the serpentine belt so I got it changed 2 days ago with new roller and tensioner aswell (even new lever) but it's still there... Could it be a loose spark plug? When this noise appeared the car started to behave weird.. Like when I'm driving 70mph on the highway and downshifting (PDK) from 7th to 6th, there is a big "clung" sound and it's like the car is hunting revs, doesn't feel as smooth as it was few weeks ago (btw my plugs and coils were replaced with my hpfp in early June by OPC).

Also weird thing, the issue disappears if driving on a slope road (downhill)

PS : no fault code

Petza914

Might be motor or transmission mounts.

SilverFrog

Hi Petza!

New engine mounts are coming (RSS).
But what about the transmission mounts? I've never read anything about PDK mounts, do they have an aftermarket counterpart?

Petza914

I actually bought a pair of these by mistake.

http://www.torquesolution.com/product-p/ts-por-010.htm

which don't fit my manual transmission. What's odd is that the description says they apply to years '99-'11 and fit manual and Tiptronic automatic transmissions, but not the PDK, but they did not fit my 05 MT. If your transmission mount looks like the photo below and you want to press is new bushings that are stiffer than stock, but a street version, I'll make you a deal on these new ones sitting on my shelf. I don't see another product on the Torque Solutions site that does specifically say it's for the PDK transmission. Or if anyone else that has this style transmission mount bracket and is interested in these, let me know.



My Manual Transmission needed this type, which I installed to replace the crumbling OEM foam rubber versions.





It looks like on the Function First website that they do have a mount for the PDK transmission as you can select it in the drop-down menu, but doesn't show a photo specific to each application, just the series of photos at the top of the page, so I'm not sure what that one looks like, but it does look like there are aftermarket trans mounts for the PDK.

http://www.function-first.com/produc...s-mount-insert


Here's my new FF mounts installed

SilverFrog

Quick follow-up on my issue : brought the car to OPC and they didn't find anything at all, as they were unable to replicate the noise, they checked spark/coils aswell and found nothing wrong.

And still no fault code

Here is what we have so far :

- A noise that only appears once the car reaches 90°C Oil temperature
- From engine bay, driver side
- Cannot be heard when the car is idling
- Cannot be heard if there is no load on the engine
- Cannot be heard if I don't press throttle pedal
- Cannot be heard if the car is not moving in 'D'

Btw here is a video of the noise I tried to record :
You have to listen very carefuly, each time i'm pressing the gas there is a shrill noise right before, that's it.

My car has PDK and i'm now worried that it could be related to the gearbox...

Also I noticed I have a loud ticking noise on the rear end of the car, passenger side, right next to the wheel, heres is a video :

I'll try to lift the car in the coming days and put it in 'D' while lifted to isolate the noise, will keep you updated, i'll also check if the transmission mounts are worn

SilverFrog

Back to update, I ordered and installed the function first transmission inserts (yellow) in addition to semi-solid engine mounts : the clicking noise is still there...

I'm very afraid it has to do with the PDK, that being said I noticed what looks to be a seepage from the PDK pan so the car will be brought to OPC again and asked them to recalibrate the gearbox and TB.

I've read other post mentioning this noise on Cayman but no one seems to get a useful answer :/

What was replaced so far since the noise appeared :

Belt
Belt tensioner
Belt tensioner lever
PDK mounts inserts
Engine mounts

Bruce In Philly

2009 C2S 170K miles

It may be your water pump. My pump made those weird noises. For me it was at startup and only cold. I would start and get an immediate chirp... then about 20 seconds later, a rattle. The rattle would go away after 20-30 seconds. I thought the rattle was comming from the exhausts as a few months ago, I had a weld break. What got me really concerned was one time I got a burning smell... I was starting and stopping the car rolling slowly.... I shoot photography from my car so I was moving along a marsh road with the window down and picked up the smell.

These new water pumps are built really well..... it appears to take a long time for them to fully fail. Some had them just fail and seize up, but I think a slow process is to blame.

To diagnose, put a stethoscope on it.... or take it to any service station that has one... you will hear it make a very consistent, almost smooth "chchchchchchchchchchchchhch". Yea figure that one out. In short, it is sounds like ball bearings without any grease.... metal-on-metal rolling.

Peace
Bruce in Philly

CAVU

Year and how many miles on the car?

SilverFrog

Hi Bruce, thank you for you message, I learned a lot about my car thanks to some threads you made on RL, I'll check the water pump asap

Early build 2008, actually has 218 000km (135.450 miles) the noise started at something like 125k or 127k miles I don't remember correctly

CAVU

Follow Bruce's lead. The mechanics stethoscope will "tell" you a lot.

BucketList

Another consideration is axle joints going bad. Just a thought since you have to be moving and it doesn't do it going downhill (which is the side of the joint that doesn't get worn).

SilverFrog

Hey guys, I will not leave this thread unresolved !

After hours and weeks of research, we potentially identified that the noise is coming from my dual-mass flywheel that is dying (the car has 135k miles and I think this item was never replaced)

I couldn't find a lot (not to say nothing) about DMFW replacement on PDK cars.

Also, when this noise apperead, I did notice a slight seepage between gearbox and engine, a Porsche tech confirmed RMS leak along with the failing DMFW.

I've ordered all the parts in order to replace it, I will try to document the operation as much as possible with pics/vids

GTSpure

Good luck friend and thanks for your updates.
The car has a lot of miles - which is very impressive..!
I would also look at the Alternator and test it. These are my 2 cents

SilverFrog

Yes this is planned, when we'll replace the dmfw with my indy friend, we will drop the engine aswell to inspect everything.

SilverFrog

Resurecting an old thread, still unresolved, the noise is still there after the whole gearbox/engine assembly was tore down in order to change the RMS and the PDK flywheel.

My guess is now that this noise comes from the gearbox but is due to an update of the PDK software a year ago which potentially changed its behavior about how it catches gears at given RPMs (I've read a thread on another forum where someone had a similar noise/issue after tunning his gearbox through a COBB Accessport and it went away once he reseted everything to stock)

I have few things to fix on my car first like alternator, breaks, once it's ready i'll bring it to my OPC and ask for a PDK software reset