Originally Posted by hotrod2448

Additional info, I have a rattle on startup sometimes. I assumed it was the timing chain noise discussed in this thread but, my dealer says it is a lifter that has bled down and that this is common on the diesel and the hybrid. Thinking it through this does make sense (I don't see the correlation with diesel and the hybrid doing it but, the noise does fit) but, still does not seem to be normal operation. Listening to it closely the last few days I can hear the rattle at start up for 2 seconds it then goes away but, there is a lifter tick I can hear that then goes away maybe 3 seconds after the rattle ends. Taking it in this Friday so hopefully there will be something that comes from that.

Originally Posted by chsu74

I get the noise every now and then. Not consistent with length between non starts.

Originally Posted by hotrod2448

Mine is similar in behavior. It makes me wonder if it is driven by where the engine comes to a stop when it's shut down causing a specific lifter or two to collapse from trying to hold a valve open with no oil pressure.

https://www.youtube.com/channel/UCf2...kvblBd3Ib7gnCA

Originally Posted by chsu74

Yeah. I would be concerned with timing chain rail guides wearing out or something like that but it sounds like lifters losing oil so its a no biggie to me.

Originally Posted by HGR

To conclude this post, at this time, I am having substantial issues, even for a person with my credentials and background to get my Dealer in OHIO, where I bought the car, to either remove the engine and replace all chains and tensioners along with the chain guides or just swap a new engine in---under my warranty.

Originally Posted by skiahh

There is not a single manufacturer anywhere that will remove an engine or replace an engine pre-emptively under any warranty. They will wait for it to fail and then replace it... if necessary. It doesn't matter how much knowledge, experience or expertise you may have.

Originally Posted by Eskimo1

Normally I'd agree whole-heartedly! Interestingly enough though, a VW owner got his dealer to take action. https://www.clubtouareg.com/threads/...noises.278594/

Originally Posted by HGR

I hate to break it to you, but the noise that you are all hearing is not “normal” or should not even be heard, during the first 150k miles of any vehicle, that has undergone reasonable care and was endowed with proper oil.

I am a managing partner of a R&D Firm that specializes in the automotive industry. My extensive “know-how” in this field (incl. my ASE Master Tech A1-A8 & A9 –Diesel Engines- and L1 certifications) gives me insights into the abyss of the workings of this TDI engine. The V6 TDI that we all here have in our cayenne diesel is actually a VW/Audi product.

As a prelude to what I am going to say and in summary for those that do not want to read my lengthy monologue, I have it black and white from my Porsche Dealer in Germany –Stuttgart Flughafen Dealer—that the noise that I had recorded from my TDI Cayenne upon startup is indeed NOT NORMAL, and should “in accordance to my service reps. own words: Never be hear”.

My company does extensive work in Germany and in the states. I own a 1997 993 Indish Rot Bi-Turbo, a 1991 964 Carrera 4, Indish Rot and a 1967 911S Bahia Rot of which some of these cars are in the care of the Flughafen Stuttgart Porsche Dealership.

In the states, I just recently purchased a 14 Cayenne in White. At the time of purchase the vehicle had some 65k miles on it and was sold by the MAG dealership in Columbus, OH. Within two months of driving, and having accumulated during that time some 3-5k miles, I noticed that the vehicle from time to time made a timing chain noise, much similar to my 2011 ML 350 Mercedes Bluetec. Due to the many problems I had with the Bluetec, I immediately knew that this was not a GOOD Sign. Nonetheless, I hoped for the better and knew that I had unlimited MILEAGE warranty on the rig.

At the first oil change, I already notified the service rep. at MAG that the vehicle was making the timing chain slapping noise indicative of a failed hydraulic timing chain tensioner. My dealer and rep. did not want to have anything to do with my complaint and just shrugged the shoulders, stating that no check engine light is equal to no problem. As anybody can think, this did not sit well with me. I approached two other dealership during my many extensive drives and they too, gave me the silliest and unprofessional remarks concerning the problem.

Fast forward, the timing chain rattle/slapping has gotten progressively worse. I now own the car for less than a 11 months, have accumulated 20k miles and have to endure this harsh unpleasant noise almost every second startup.

The noise is not what disturbs me, but what is happening in reality behind the scenes. What do I mean by that? Simply put, the V6 Audi/VW Diesel is an impressive fuel sipping, torquey mule, but has one major design flaw: It has dependent upon the build year up to 4 timing chains. Yes, you heard that correctly: 4 timing chains. The oil pump itself is driven by a dedicated chain drive!

There are timing chain guides and tensioners for the chains. The guides are either made of metal and are coated with a nylon compound or made entirely from a non-metal material. The rattle/slapping upon start-up doesn’t cause the chain to loose tension exactly because the driver sprocket on the crank or intermediate driven gear sprocket keep the tension in the pulling direction, but the slapping happens on the loose, tension-less side of the assembly. Think of it like your ten speed on your bike. If you pedal, the top of the chain stays tight and the bottom is relaxed or firm. Why is it firm? The spring loaded tensioner/ derailleur keeps the chain from slacking. In the case of the hydraulic/oil tensioner, this is no longer happening in our cars, which can have catastrophic failure in case the chain links do not seat properly on the sprockets and thus causes the timing chain to jump, thus potentially risking a valve and piston collision.

The slapping and rattling causes also excessive wear in the coated chain guides along with potentially breaking “all-plastic/nylon” guides. Where does all that end up? It ends up in the oil pan and contaminates the engine more and more, damaging the rest of the engine, while the problem persists.

For those of us that start their engines more than twice a day, the wear and risk increases exponentially.

Here comes the technical aspect of things:

The timing chain tensioner is comprised of a spring, check valve, in some instances a locking mechanism, etc. (I am not sure if this audi engine has a locking mechanism –the tensioner extens and locks, every time it extens a set amount, similar to a ratchet mechanism). In our engines, the check valves, maintaining oil pressure (peak pressure from the oiling mechanisms operation), are no longer holding pressure.

Why is this the case? The oil has been contaminated for too long or the oil was just the wrong oil grade, or the engine management, ECU Programming, is not adequate.

Well, I would recommend using T-6 Engine Oil in these sumps, but as I have done –following dealer recommended oil change criteria—I let the dealer put into it, what they “think” is the correct oil.

The oil change interval of 3k miles, that the MAG dealer forced upon me, is reasonable.

Here is now the kicker though: All of our TDIs have a major ECU programming fault /design flaw. What do I mean by that? Forget the Diesel Gate Scandal and focus on the technology here. Our Prosche Diesel TDI engine has an oxidizer, DPF and SCR exhaust assembly. The DPF is the diesel particulate filter, the SCR is NOx catalyst and so on. The DPF/oxidizer traps soot particles in it during the normal operation of the diesel engine. When the DPF Pressure Differential Sensor, which is reading in front and after the DPF the exhaust back pressure , senses a too high discrepancy from upstream to downstream, the engine goes into an ACTIVE DPF REGENERATION MODE. What does an ACTIVE Diesel Particulate Filter Regeneration mean? The engine programming should have recorded a “high” trigger value and have stored such in the ECU. Once the engine reaches operating temperature the next time or within that “drive cycle” for some pre-defined mileage travelling over approximately 50 MPG, the engine starts its regeneration—the engine starts running rich—more fuel is injected—the boost is increased, injection timing altered, valve timing altered, the cooling fans are running, when they really should not.

All of this combines to increase the in-cylinder combustion temperature from a normal highway cruising temperature of 300-400 C to almost 800 C during the same driving condition. That high temperature in the combustion chamber, causes the exhaust upstream the DPF to heat up extensively.

All of this puts tremendous load and stress on the valves, pistons, turbocharger and exhaust components! The engine oil also increases a good 20C during this process. Diesel run sooty, we all know that, that is why the engine oil is immediately black again after an oil change—there is so much soot and carbon suspended in the oil and metal surfaces within the block, that the fresh oil just turns black again within minutes of an oil change.

That high carbo/soot content in the oil clumps and interlinks when the diesel engine reaches these high Active Regeneration temperatures. These chains of molecules then build-up around components like piston compression rings, piston oil control rings, “chain tensioner check valves” etc. Here lies the fundamental problem—the engine management layout/mapping.

These EU Diesel cars –Mercedes Bluetecs are really the worst--- are designed and programmed to rely heavily on PASSIVE REGENERATION. Passive Regeneration occurs when engines are operated in the x> 3000 rpm range and under X>50% load, for an extensive period of time. You have high CFM throughput (high engine rpm), higher temperatures (max only 470 C) for say 20 minutes of driving: the Soot just vaporized itself along with being properly exhausted/vented from the DPF and SCR.

In Europe these diesel engines from Mercedes and VW /Audi do not experience the same failures or problems we experience in the US. Our speed limits and cruising speeds almost entirely prevent the exhaust from passively regenerating.

Mercedes Bluetec Sprinters in the US also don’t have any of the problems that their cousins the ML or GL 350 Bluetec from 2010 through 2014 had. The Sprinter cargo van operates at 70 MPG at around 3k to 3.5k engine rpm with an above 50% engine load. There the exhaust system passively regenerates.

The SCR and Urea injection even further compounds the problem. That is why the Diesel Gate Scandal even occurred. Porsche, VW and Audi (I say Mercedes too), who knows about BMW (It is to be noted that Bosch supplies all of them with ECUs and sensors, food for thought), eliminated the injection of UREA or DEF (Diesel Exhaust Fluid) below a threshold of ambient environment temperatures. Why you ask? Well simply the exhaust temperature downstream the urea injection nozzle would have been too cold for the urea to fully evaporate. If the DEF / UREA does not fully evaporate in the exhaust stream, within the SCR or selective catalytic reduction filter, then the DEF will crystalize therein and cause the filter to plug up. The engine management system however is not smart enough though to realize when and at what point the SCR filter is getting plugged (no differential sensors there, only temp sensors and upstream and downstream of the SCR NOx sensors).

I have not had any NOx sensor go bad on the Cayenne yet, however on my 2011 Bluetec, I had at least six NOx sensors installed over a course of 120 k miles. The AdBlue, also called DEF or Diesel Exhaust Fluid Tank/Reservoir in the ML 350 Bluetec also failed twice.

Let’s backtrack here:

The active regeneration method/mode of programming also compounds the life and regen cycle of the DPF (diesel particulate filter). When the engine runs hot during the active regeneration, the oil gets approximately 20 C hotter, overall. The oil getting squirted onto the bottom of the pistons by means of the oilers causes the oil to evaporate during said cycle---yes oil can evaporate. The oil gets then drawn and vented from the crank case ventilation into the upstream of the turbocharger cold air stream (vacuum side of the turbocharger in between the air filter box and the compressor housing inlet of the turbocharger). That is why you see oil laying around the turbocharger air inlet grommet. The more often the engine goes into an active regeneration, the more oil you have in the turbocharger, intake, combustion chamber.

Because you are now pushing oil into the combustion chamber, the combustion process and exhaust gasses get dirtier (sootier) and therefore cause the DPF to plug up even sooner then before.

Mercedes recommends explicitly in the owner’s manual of the 350 ML Bluetec to drive every 600 miles for an extensive period of 20 minutes at HIGHWAY speeds ( MB is hoping on passive regeneration).

In short, our diesels are programmed to self-destruct! Class Action Diesel Engine Failure Lawsuit?

In the meantime, I would recommend driving the Cayenne or any EU diesel (especially the Bluetec) in lower gears, when not on the Highway to keep the exhaust temp and exhaust CFM (cubic feet per minute) high to invoke passive regeneration.

On the Mercedes Star Diagnostic System the ECU can be read and determined how many miles the vehicle has driven since the last active regeneration.

In the US a good mileage number would be 2000 miles! Keep in mind though the ECU Check Engine Light or CEL or MIL only comes on if two active regenerations occurred within a 150 mile driving interval. That is ridiculous!

I am currently working at getting either the engine replaced or the timing chains, timing chain tensioners and timing chain guides replaced ---under my Porsche Certified Pre-Owned Warranty. My recommendation is that you do TOO.

P.S.: The Porsche and Mercedes Dealers in OHIO, that I have been to so far, are all inadequately trained or equipped or just want to sell Porsche drivers as IDIOTS, I included, because they think they can get away with it.

Originally Posted by HGR

I hate to break it to you, but the noise that you are all hearing is not “normal” or should not even be heard, during the first 150k miles of any vehicle, that has undergone reasonable care and was endowed with proper oil.

I am a managing partner of a R&D Firm that specializes in the automotive industry. My extensive “know-how” in this field (incl. my ASE Master Tech A1-A8 & A9 –Diesel Engines- and L1 certifications) gives me insights into the abyss of the workings of this TDI engine. The V6 TDI that we all here have in our cayenne diesel is actually a VW/Audi product.

As a prelude to what I am going to say and in summary for those that do not want to read my lengthy monologue, I have it black and white from my Porsche Dealer in Germany –Stuttgart Flughafen Dealer—that the noise that I had recorded from my TDI Cayenne upon startup is indeed NOT NORMAL, and should “in accordance to my service reps. own words: Never be hear”.

My company does extensive work in Germany and in the states. I own a 1997 993 Indish Rot Bi-Turbo, a 1991 964 Carrera 4, Indish Rot and a 1967 911S Bahia Rot of which some of these cars are in the care of the Flughafen Stuttgart Porsche Dealership.

In the states, I just recently purchased a 14 Cayenne in White. At the time of purchase the vehicle had some 65k miles on it and was sold by the MAG dealership in Columbus, OH. Within two months of driving, and having accumulated during that time some 3-5k miles, I noticed that the vehicle from time to time made a timing chain noise, much similar to my 2011 ML 350 Mercedes Bluetec. Due to the many problems I had with the Bluetec, I immediately knew that this was not a GOOD Sign. Nonetheless, I hoped for the better and knew that I had unlimited MILEAGE warranty on the rig.

At the first oil change, I already notified the service rep. at MAG that the vehicle was making the timing chain slapping noise indicative of a failed hydraulic timing chain tensioner. My dealer and rep. did not want to have anything to do with my complaint and just shrugged the shoulders, stating that no check engine light is equal to no problem. As anybody can think, this did not sit well with me. I approached two other dealership during my many extensive drives and they too, gave me the silliest and unprofessional remarks concerning the problem.

Fast forward, the timing chain rattle/slapping has gotten progressively worse. I now own the car for less than a 11 months, have accumulated 20k miles and have to endure this harsh unpleasant noise almost every second startup.

The noise is not what disturbs me, but what is happening in reality behind the scenes. What do I mean by that? Simply put, the V6 Audi/VW Diesel is an impressive fuel sipping, torquey mule, but has one major design flaw: It has dependent upon the build year up to 4 timing chains. Yes, you heard that correctly: 4 timing chains. The oil pump itself is driven by a dedicated chain drive!

There are timing chain guides and tensioners for the chains. The guides are either made of metal and are coated with a nylon compound or made entirely from a non-metal material. The rattle/slapping upon start-up doesn’t cause the chain to loose tension exactly because the driver sprocket on the crank or intermediate driven gear sprocket keep the tension in the pulling direction, but the slapping happens on the loose, tension-less side of the assembly. Think of it like your ten speed on your bike. If you pedal, the top of the chain stays tight and the bottom is relaxed or firm. Why is it firm? The spring loaded tensioner/ derailleur keeps the chain from slacking. In the case of the hydraulic/oil tensioner, this is no longer happening in our cars, which can have catastrophic failure in case the chain links do not seat properly on the sprockets and thus causes the timing chain to jump, thus potentially risking a valve and piston collision.

The slapping and rattling causes also excessive wear in the coated chain guides along with potentially breaking “all-plastic/nylon” guides. Where does all that end up? It ends up in the oil pan and contaminates the engine more and more, damaging the rest of the engine, while the problem persists.

For those of us that start their engines more than twice a day, the wear and risk increases exponentially.

Here comes the technical aspect of things:

The timing chain tensioner is comprised of a spring, check valve, in some instances a locking mechanism, etc. (I am not sure if this audi engine has a locking mechanism –the tensioner extens and locks, every time it extens a set amount, similar to a ratchet mechanism). In our engines, the check valves, maintaining oil pressure (peak pressure from the oiling mechanisms operation), are no longer holding pressure.

Why is this the case? The oil has been contaminated for too long or the oil was just the wrong oil grade, or the engine management, ECU Programming, is not adequate.

Well, I would recommend using T-6 Engine Oil in these sumps, but as I have done –following dealer recommended oil change criteria—I let the dealer put into it, what they “think” is the correct oil.

The oil change interval of 3k miles, that the MAG dealer forced upon me, is reasonable.

Here is now the kicker though: All of our TDIs have a major ECU programming fault /design flaw. What do I mean by that? Forget the Diesel Gate Scandal and focus on the technology here. Our Prosche Diesel TDI engine has an oxidizer, DPF and SCR exhaust assembly. The DPF is the diesel particulate filter, the SCR is NOx catalyst and so on. The DPF/oxidizer traps soot particles in it during the normal operation of the diesel engine. When the DPF Pressure Differential Sensor, which is reading in front and after the DPF the exhaust back pressure , senses a too high discrepancy from upstream to downstream, the engine goes into an ACTIVE DPF REGENERATION MODE. What does an ACTIVE Diesel Particulate Filter Regeneration mean? The engine programming should have recorded a “high” trigger value and have stored such in the ECU. Once the engine reaches operating temperature the next time or within that “drive cycle” for some pre-defined mileage travelling over approximately 50 MPG, the engine starts its regeneration—the engine starts running rich—more fuel is injected—the boost is increased, injection timing altered, valve timing altered, the cooling fans are running, when they really should not.

All of this combines to increase the in-cylinder combustion temperature from a normal highway cruising temperature of 300-400 C to almost 800 C during the same driving condition. That high temperature in the combustion chamber, causes the exhaust upstream the DPF to heat up extensively.

All of this puts tremendous load and stress on the valves, pistons, turbocharger and exhaust components! The engine oil also increases a good 20C during this process. Diesel run sooty, we all know that, that is why the engine oil is immediately black again after an oil change—there is so much soot and carbon suspended in the oil and metal surfaces within the block, that the fresh oil just turns black again within minutes of an oil change.

That high carbo/soot content in the oil clumps and interlinks when the diesel engine reaches these high Active Regeneration temperatures. These chains of molecules then build-up around components like piston compression rings, piston oil control rings, “chain tensioner check valves” etc. Here lies the fundamental problem—the engine management layout/mapping.

These EU Diesel cars –Mercedes Bluetecs are really the worst--- are designed and programmed to rely heavily on PASSIVE REGENERATION. Passive Regeneration occurs when engines are operated in the x> 3000 rpm range and under X>50% load, for an extensive period of time. You have high CFM throughput (high engine rpm), higher temperatures (max only 470 C) for say 20 minutes of driving: the Soot just vaporized itself along with being properly exhausted/vented from the DPF and SCR.

In Europe these diesel engines from Mercedes and VW /Audi do not experience the same failures or problems we experience in the US. Our speed limits and cruising speeds almost entirely prevent the exhaust from passively regenerating.

Mercedes Bluetec Sprinters in the US also don’t have any of the problems that their cousins the ML or GL 350 Bluetec from 2010 through 2014 had. The Sprinter cargo van operates at 70 MPG at around 3k to 3.5k engine rpm with an above 50% engine load. There the exhaust system passively regenerates.

The SCR and Urea injection even further compounds the problem. That is why the Diesel Gate Scandal even occurred. Porsche, VW and Audi (I say Mercedes too), who knows about BMW (It is to be noted that Bosch supplies all of them with ECUs and sensors, food for thought), eliminated the injection of UREA or DEF (Diesel Exhaust Fluid) below a threshold of ambient environment temperatures. Why you ask? Well simply the exhaust temperature downstream the urea injection nozzle would have been too cold for the urea to fully evaporate. If the DEF / UREA does not fully evaporate in the exhaust stream, within the SCR or selective catalytic reduction filter, then the DEF will crystalize therein and cause the filter to plug up. The engine management system however is not smart enough though to realize when and at what point the SCR filter is getting plugged (no differential sensors there, only temp sensors and upstream and downstream of the SCR NOx sensors).

I have not had any NOx sensor go bad on the Cayenne yet, however on my 2011 Bluetec, I had at least six NOx sensors installed over a course of 120 k miles. The AdBlue, also called DEF or Diesel Exhaust Fluid Tank/Reservoir in the ML 350 Bluetec also failed twice.

Let’s backtrack here:

The active regeneration method/mode of programming also compounds the life and regen cycle of the DPF (diesel particulate filter). When the engine runs hot during the active regeneration, the oil gets approximately 20 C hotter, overall. The oil getting squirted onto the bottom of the pistons by means of the oilers causes the oil to evaporate during said cycle---yes oil can evaporate. The oil gets then drawn and vented from the crank case ventilation into the upstream of the turbocharger cold air stream (vacuum side of the turbocharger in between the air filter box and the compressor housing inlet of the turbocharger). That is why you see oil laying around the turbocharger air inlet grommet. The more often the engine goes into an active regeneration, the more oil you have in the turbocharger, intake, combustion chamber.

Because you are now pushing oil into the combustion chamber, the combustion process and exhaust gasses get dirtier (sootier) and therefore cause the DPF to plug up even sooner then before.

Mercedes recommends explicitly in the owner’s manual of the 350 ML Bluetec to drive every 600 miles for an extensive period of 20 minutes at HIGHWAY speeds ( MB is hoping on passive regeneration).

In short, our diesels are programmed to self-destruct! Class Action Diesel Engine Failure Lawsuit?

In the meantime, I would recommend driving the Cayenne or any EU diesel (especially the Bluetec) in lower gears, when not on the Highway to keep the exhaust temp and exhaust CFM (cubic feet per minute) high to invoke passive regeneration.

On the Mercedes Star Diagnostic System the ECU can be read and determined how many miles the vehicle has driven since the last active regeneration.

In the US a good mileage number would be 2000 miles! Keep in mind though the ECU Check Engine Light or CEL or MIL only comes on if two active regenerations occurred within a 150 mile driving interval. That is ridiculous!

I am currently working at getting either the engine replaced or the timing chains, timing chain tensioners and timing chain guides replaced ---under my Porsche Certified Pre-Owned Warranty. My recommendation is that you do TOO.

P.S.: The Porsche and Mercedes Dealers in OHIO, that I have been to so far, are all inadequately trained or equipped or just want to sell Porsche drivers as IDIOTS, I included, because they think they can get away with it.

Originally Posted by hotrod2448

Mine is similar in behavior. It makes me wonder if it is driven by where the engine comes to a stop when it's shut down causing a specific lifter or two to collapse from trying to hold a valve open with no oil pressure.

https://www.youtube.com/channel/UCf2...kvblBd3Ib7gnCA