Rattle sound at low speed
#1
7th Gear
Thread Starter
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Hello,
I have a 2.9TT Cayenne S with PDCC and air suspension.
Please advise where to look: on a warm car, when I release the throttle (only in the RPM range of 700-1000) at speeds of 20-40 km/h, I hear a rattle from under the hood for a couple of seconds. The sounds seem to be coming from near the engine compartment partition. If I give it some gas, the rattle disappears immediately.
There is no such issue on a cold engine, and there is no problem at higher speeds. There are no error codes. The acceleration is excellent. The issue occurs both with and without the air conditioning on.
Checked all the protective covers - they're not loose, and we've also checked the drain plug cover. The dealer only noticed a slight play in the wastegate shaft but isn't sure if that's the cause
I have a 2.9TT Cayenne S with PDCC and air suspension.
Please advise where to look: on a warm car, when I release the throttle (only in the RPM range of 700-1000) at speeds of 20-40 km/h, I hear a rattle from under the hood for a couple of seconds. The sounds seem to be coming from near the engine compartment partition. If I give it some gas, the rattle disappears immediately.
There is no such issue on a cold engine, and there is no problem at higher speeds. There are no error codes. The acceleration is excellent. The issue occurs both with and without the air conditioning on.
Checked all the protective covers - they're not loose, and we've also checked the drain plug cover. The dealer only noticed a slight play in the wastegate shaft but isn't sure if that's the cause
#2
Rennlist Member
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What year and how many kms on this vehicle?
30kmh/19mph in 3rd gear, correct? This is one of the speed/rpm ranges where the driveline vibration/rumble is present.
However, the sound in the video sounds like a rattle, not a rumble. Do you feel the vibration in the seat or floor?
If it is a rattle, it sounds like a loose heat shield. An inspection under the car to check the several heat shields is the way to see if that is the issue.
30kmh/19mph in 3rd gear, correct? This is one of the speed/rpm ranges where the driveline vibration/rumble is present.
However, the sound in the video sounds like a rattle, not a rumble. Do you feel the vibration in the seat or floor?
If it is a rattle, it sounds like a loose heat shield. An inspection under the car to check the several heat shields is the way to see if that is the issue.
Last edited by chassis; 09-15-2023 at 12:46 PM.
#3
7th Gear
Thread Starter
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Thx for reply!
I do not feel any vibration, most likely it should be something like heatshield, but it is pretty strange that sound appears only at those rpms.
Delaer yesterday checked most of possible issues and also tried heatshield. But we will give another try, thx!
I do not feel any vibration, most likely it should be something like heatshield, but it is pretty strange that sound appears only at those rpms.
Delaer yesterday checked most of possible issues and also tried heatshield. But we will give another try, thx!
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chassis (09-15-2023)
#4
Burning Brakes
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Thx for reply!
I do not feel any vibration, most likely it should be something like heatshield, but it is pretty strange that sound appears only at those rpms.
Delaer yesterday checked most of possible issues and also tried heatshield. But we will give another try, thx!
I do not feel any vibration, most likely it should be something like heatshield, but it is pretty strange that sound appears only at those rpms.
Delaer yesterday checked most of possible issues and also tried heatshield. But we will give another try, thx!
The attachment from Porsche shows where to put a stethoscope to differentiate the HPFP from the timing wheel assy.
Check out this thread and play the two videos they posted on the Audi V6 (same engine) Panamera-
18 Panamera What the heck is that noise! - Rennlist - Porsche Discussion Forums
Last edited by Ericson38; 09-15-2023 at 01:16 PM.
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#5
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The 2.9 is coarse. Anything that can vibrate will vibrate at its resonant frequency. The input vibration frequency from the engine is proportional to engine rpm. Therefore whatever is vibrating has a resonant frequency at the engine rpm at which you are observing it.
#6
7th Gear
Thread Starter
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car has just 40k miles on it and still on waranty , production year is end of 2017. Till the last service on dealership it was really perfect, so I have nothing against 2,9tt.
In this case it should rattle at idle rpms , but it happens only on the read.
BTW how americal dealers are treating this cases? They are considered as warranty claims?
The input vibration frequency from the engine is proportional to engine rpm
BTW how americal dealers are treating this cases? They are considered as warranty claims?
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chassis (09-16-2023)
#7
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car has just 40k miles on it and still on waranty , production year is end of 2017. Till the last service on dealership it was really perfect, so I have nothing against 2,9tt.
In this case it should rattle at idle rpms , but it happens only on the read.
BTW how americal dealers are treating this cases? They are considered as warranty claims?
In this case it should rattle at idle rpms , but it happens only on the read.
BTW how americal dealers are treating this cases? They are considered as warranty claims?
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#8
7th Gear
Thread Starter
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![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
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chassis (09-16-2023)
#9
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Good deal, didn't know that.
#10
Burning Brakes
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car has just 40k miles on it and still on waranty , production year is end of 2017. Till the last service on dealership it was really perfect, so I have nothing against 2,9tt.
In this case it should rattle at idle rpms , but it happens only on the read.
BTW how americal dealers are treating this cases? They are considered as warranty claims?
In this case it should rattle at idle rpms , but it happens only on the read.
BTW how americal dealers are treating this cases? They are considered as warranty claims?
B9 S4 EA839 Series Engine Rocker Arm Failure - AudiWorld Forums
B9 S4 rocker arm issue. - Page 10 (audizine.com)
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chassis (09-16-2023),
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#11
7th Gear
Thread Starter
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For some early EA839 engines, there were failures of the roller bearings in the rocker arm pivots. But that has not been posted as a failure in this forum that I know of.
B9 S4 EA839 Series Engine Rocker Arm Failure - AudiWorld Forums
B9 S4 rocker arm issue. - Page 10 (audizine.com)
B9 S4 EA839 Series Engine Rocker Arm Failure - AudiWorld Forums
B9 S4 rocker arm issue. - Page 10 (audizine.com)
Thx for advice! Looked videos with described issue - frequency of ticking is couple of times lower than mine
#13
7th Gear
Thread Starter
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Yes! Heat isolation plate between exhaust and bottom of the car wasn’t installed properly and additionally dealer replaced one of the bushings of the exhaust pipe. Now it perfect
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chassis (11-15-2023)
#14
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Mine ended up being a loose top engine mount bolt. Didn’t think those could just loosen on their own, maybe they didn’t tighten it after the service or something (assuming they loosen for access, no idea).
#15
Rennlist Member