Cayenne rattle noise after cold startup
10-11-2007, 04:53 PM
#1
Burning Brakes
Thread Starter
Join Date: Oct 2007
Location: Hell..err Tucson where its hot as hell
Posts: 990
Likes: 0
Received 0 Likes
on
0 Posts
Cayenne rattle noise after cold startup
Try my best not to be such a dumbass newb on here (hopefully you guys will be more forgiving since I just said that 
)
But my 2004 S has a rattle noise coming from underneath upon cold startup and it is in direct correlation with revs. Like the higher I rev when cold, the louder and faster the rattle. It is only when it is cold and the idol revs are a tad high. Once she warms up, then the rattle is gone.
Could it be the cats? Just wondering if any of my fellow owners have experienced the same thing or not? I have 2 more months of factory warranty left and have already been taking it in for pretty much everything under the sun the last two months. But I have two more small things that I will be addressing soon (before warranty runs out), and am just wondering if that should be addressed as well? Like....is it a problem, or normal?
Thanks
Jason
(oh and if you guys are not as forgiving because I am a newb, how about because I am on Percocet 10/325's for back pain? Maybe that could forgive dumb posts because I know not of what I do? )
)But my 2004 S has a rattle noise coming from underneath upon cold startup and it is in direct correlation with revs. Like the higher I rev when cold, the louder and faster the rattle. It is only when it is cold and the idol revs are a tad high. Once she warms up, then the rattle is gone.
Could it be the cats? Just wondering if any of my fellow owners have experienced the same thing or not? I have 2 more months of factory warranty left and have already been taking it in for pretty much everything under the sun the last two months. But I have two more small things that I will be addressing soon (before warranty runs out), and am just wondering if that should be addressed as well? Like....is it a problem, or normal?
Thanks
Jason
(oh and if you guys are not as forgiving because I am a newb, how about because I am on Percocet 10/325's for back pain? Maybe that could forgive dumb posts because I know not of what I do? )
10-11-2007, 06:01 PM
#2
Moderator !x4
WOW your brave.
1 - Join the board as a member
2 - Search Cold Start
There is a wealth of knowledge of these trucks on here you would be wise to search first, then read the manual then buy the Tech Manual off of Ebay to learn.
The cold start behaviour you describe is programmed. At start up it runs in 1st gear until the cats warm up for emissions control.
The rattle you describe could be loose brackets but it could just be the high rev racing rattle the car makes naturally.
1 - Join the board as a member
2 - Search Cold Start
There is a wealth of knowledge of these trucks on here you would be wise to search first, then read the manual then buy the Tech Manual off of Ebay to learn.
The cold start behaviour you describe is programmed. At start up it runs in 1st gear until the cats warm up for emissions control.
The rattle you describe could be loose brackets but it could just be the high rev racing rattle the car makes naturally.
10-11-2007, 10:05 PM
#3
Racer
Join Date: Jul 2006
Posts: 366
Likes: 0
Received 0 Likes
on
0 Posts
1. Ditto what our esteemed moderator said.
2. This is probably a stupid question in its own right, but is the noise definitely new and are you sure it is coming from the nether regions near the cats, instead of up higher, in the land of the valve train or belt tensioner?
3. No excuses here for being impaired. We are ALL impaired here, one way or another.
4. No drugs on the forum unless you share. And come back with something better than Percocet. Our opiate receptors will kick its butt and take its lunch money.
2. This is probably a stupid question in its own right, but is the noise definitely new and are you sure it is coming from the nether regions near the cats, instead of up higher, in the land of the valve train or belt tensioner?
3. No excuses here for being impaired. We are ALL impaired here, one way or another.
4. No drugs on the forum unless you share. And come back with something better than Percocet. Our opiate receptors will kick its butt and take its lunch money.
10-11-2007, 10:26 PM
#5
Burning Brakes
Thread Starter
Join Date: Oct 2007
Location: Hell..err Tucson where its hot as hell
Posts: 990
Likes: 0
Received 0 Likes
on
0 Posts
1. Ditto what our esteemed moderator said.
2. This is probably a stupid question in its own right, but is the noise definitely new and are you sure it is coming from the nether regions near the cats, instead of up higher, in the land of the valve train or belt tensioner?
3. No excuses here for being impaired. We are ALL impaired here, one way or another.
4. No drugs on the forum unless you share. And come back with something better than Percocet. Our opiate receptors will kick its butt and take its lunch money.
2. This is probably a stupid question in its own right, but is the noise definitely new and are you sure it is coming from the nether regions near the cats, instead of up higher, in the land of the valve train or belt tensioner?
3. No excuses here for being impaired. We are ALL impaired here, one way or another.
4. No drugs on the forum unless you share. And come back with something better than Percocet. Our opiate receptors will kick its butt and take its lunch money.
2. It definitely sounds as if it is not coming from the top end of the motor (valvetrain), nor the bottom end (camshaft, crankshaft bearings etc..). I SUSPECTED it possibly be cat related, but ??? I AM not a stranger to cars, having been an engine builder for a number of years, but it was all mostly muscle cars etc... But I am also not afraid to admit, mechanically wise...I am WAY OUT of my league regarding Porsche so...
But like I had said...it is only there when it is first started in the morning, and is not present at idle. Only when I "goose" the gas it rattles and is RPM related. However, when she warms up (gets to the point where she takes off in 2ND gear instead of 1ST) the rattle....even if I gas her good...is gone. No mas.
3. Then I should fit in nicely
4. Awww shucks
Okay...I promise to try and hit my doc up for some Oxycontin next visit okay? 
Thanks, Jason
10-11-2007, 10:33 PM
#6
Burning Brakes
Thread Starter
Join Date: Oct 2007
Location: Hell..err Tucson where its hot as hell
Posts: 990
Likes: 0
Received 0 Likes
on
0 Posts
Really? The noise IS RPM related, but definitely seems to be coming from underneath. And for most mechanical engine noises, aren't they usually hidden due to the thicker viscosity of the oil at cold start up? Therefore the thicker oil taking the the "gaps" due to wear, and would get more pronounced as the oil heats up?
I mean....I had a 1992 Camaro Z28 (25th Anniversary) Heritage Edition 5.7 TPI car A LONG time ago, and I remember when my cats charcoal filter element broke up at around 100k miles. It made a LOUD *** rattle noise, but that noise was present all the time, not just on cold starts. I dunno.
I will be taking her back to the dealer atleast once more before the factory warranty is up due to the little speakers in the rear (by the hatch) seem to maybe be blown as they have a lot of static coming from them when Rush is playing
Plus I have an inside rear hatch bulb out (that they JUST SO didn't notice when they readjusted it last time it was in a week ago).
I will mention the rattle, and post back here what I find out so that maybe others can learn
I mean....I had a 1992 Camaro Z28 (25th Anniversary) Heritage Edition 5.7 TPI car A LONG time ago, and I remember when my cats charcoal filter element broke up at around 100k miles. It made a LOUD *** rattle noise, but that noise was present all the time, not just on cold starts. I dunno.
I will be taking her back to the dealer atleast once more before the factory warranty is up due to the little speakers in the rear (by the hatch) seem to maybe be blown as they have a lot of static coming from them when Rush is playing
Plus I have an inside rear hatch bulb out (that they JUST SO didn't notice when they readjusted it last time it was in a week ago).I will mention the rattle, and post back here what I find out so that maybe others can learn
Trending Topics
10-16-2007, 04:07 PM
#8
Sounds like it's not exhaust rattle (which probably wouldn't go away just because the idle smooths out when the engine is warmer.)
If the car has 100K miles or thereabouts, it could be piston slap.
Could be a valve lifter issue, maybe oil grade related.
Depending upon service history, the dealer should be able to diagnose from experience. Of course, it could be all kinds of in-take plumbing etc., but if it's rpm-related and cold-only, I'd be looking for things that reciprocate and expand when warm ... like pistons.
If the car has 100K miles or thereabouts, it could be piston slap.
Could be a valve lifter issue, maybe oil grade related.
Depending upon service history, the dealer should be able to diagnose from experience. Of course, it could be all kinds of in-take plumbing etc., but if it's rpm-related and cold-only, I'd be looking for things that reciprocate and expand when warm ... like pistons.
10-17-2007, 12:04 AM
#9
Burning Brakes
Thread Starter
Join Date: Oct 2007
Location: Hell..err Tucson where its hot as hell
Posts: 990
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like it's not exhaust rattle (which probably wouldn't go away just because the idle smooths out when the engine is warmer.)
If the car has 100K miles or thereabouts, it could be piston slap.
Could be a valve lifter issue, maybe oil grade related.
Depending upon service history, the dealer should be able to diagnose from experience. Of course, it could be all kinds of in-take plumbing etc., but if it's rpm-related and cold-only, I'd be looking for things that reciprocate and expand when warm ... like pistons.
If the car has 100K miles or thereabouts, it could be piston slap.
Could be a valve lifter issue, maybe oil grade related.
Depending upon service history, the dealer should be able to diagnose from experience. Of course, it could be all kinds of in-take plumbing etc., but if it's rpm-related and cold-only, I'd be looking for things that reciprocate and expand when warm ... like pistons.
I guess I have always thought that the exact opposite is true because when the oil is the coldest (i.e. first startup in the morning etc...) then it is obviously the thickest and therefore "takes up the slack" for a lack of a better word, and the ticking/knocking/rattles begin AFTER the engine heats up and the oil becomes thinner per se.
And now as I am thinking about it more as I am typing this reply...I understand that due to initial oil starvation, you CAN get (obviously depending different makes/models...I know my old 2002 WS6 "Ram Air" Trans Am that was LS1 V8 equipped was NOTORIOUS for piston slap), but you can get an initial amount of valve/lifter ticking..but pressure builds up rather quickly and it goes away. However what I am noticing...MY rattle is always present as the Cayenne is in, and I am assuming here because I know DICK of these cars, but like when it is operating in "closed loop" mode for higher idle for a predetermined amount of time, until it goes into open loop so that the cats can heat up and start sending accurate oxygen sensor feedback for proper fuel/air mixture, throttle position, etc... So the rattle is ONLY present while in the initial cold start loop mode. As soon as the idle comes down, I can rev and nada...nothing.
But hey, this could at least be a good start in getting to know possible problems so that I can accurately describe it to the service tech on my next visit. Thanks again guys for helping me brainstorm with this issue
10-17-2007, 12:41 AM
#10
Well, I was just passing through this thread on my way to searching for opinions on snow tires, but I still think it might be piston slap on a cold startup.
I think you've raised several issues in addition to the start of the thread and I'd only advise you take the car to a Porsche dealer and post back to the forum with their observations.
Anyway, regardless of old, dry hydraulic lifters needing to "pump up" on oil pressure, I think you're describing the noise of a high mileage (what's the mileage on your Cayenne S?) engine where the cylinder bore and piston shape have gradually worn apart. But that's something consistent with 80K-150K miles, not 40-80K miles.
If this were my Cayenne, I'd be asking the selling dealer to diagnose the symptoms based on their experience and information.
When I was involved in owning and operating an independent Porsche shop, I learned that some owners would come in and describe a "squeak" only to find it was what I would describe as the harsh impact of metal-on-metal when a transmission joint had exploded into two pieces. Other customers would describe a broken chassis member or frame dragging on the road only to find it was a leaf in the fan of the air-conditioning blower.
Good luck with the noise, I hope you keep posting as you progress through the diagnosis.
I think you've raised several issues in addition to the start of the thread and I'd only advise you take the car to a Porsche dealer and post back to the forum with their observations.
Anyway, regardless of old, dry hydraulic lifters needing to "pump up" on oil pressure, I think you're describing the noise of a high mileage (what's the mileage on your Cayenne S?) engine where the cylinder bore and piston shape have gradually worn apart. But that's something consistent with 80K-150K miles, not 40-80K miles.
If this were my Cayenne, I'd be asking the selling dealer to diagnose the symptoms based on their experience and information.
When I was involved in owning and operating an independent Porsche shop, I learned that some owners would come in and describe a "squeak" only to find it was what I would describe as the harsh impact of metal-on-metal when a transmission joint had exploded into two pieces. Other customers would describe a broken chassis member or frame dragging on the road only to find it was a leaf in the fan of the air-conditioning blower.
Good luck with the noise, I hope you keep posting as you progress through the diagnosis.
