2004-2006 Cayenne Turbo slight engine knock

[Roxie 1]

Hi, I'd like to ask a question that has been asked, discussed, youtube videoed etc...  My apologies, but I've read most of them and haven't found anything similar.  I'm looking at a 2004-2006 Cayenne Turbo that I don't want to turn into an engine money pit.  I've listened to 8, all cold and most have a very slight knock on the drivers side of the engine.  I'm wondering if this is the beginning to the end or some explainable sound.  You can only hear it once it drops to a low idle.  I went to my local dealer in Denver and they stated they have no way to diagnose, would not perform a new car inspection, but would do a compression check.  I realize this is tough to know when the dreaded engine knock may come due to extreme cold, piston expansion, etc...etc...  I'm also aware that the turbos were less prone.  If I'm going to drop a new engine into an old cayenne, I'd rather do it on a $10k one than $18k which is the present range for a 2004-2005 in CO.  Thanks for anyone's help and as a newbie, I hope to purchase a Cayenne and give back via DIY but don't really want to deal with engine issues for 200k+.  Thanks again, Frank  

[bigbuzuki 28]

Low viscosity oil 0w-40  can produce knock. Changing to a higher viscosity oil can quiet things down.

 

Piston slap and cylinder wall scoring can cause the knock and is what you have been reading about.

 

For peace of mind you can get the cylinder borescoped to confirm no cylinder wall damage.

 

If the Turbo cars your considering have high mileage, there's a minimal chance that you would have cylinder wall issues.

Edited December 30, 2016 by bigbuzuki

[lewisweller 79]

The turbo had a different cylinder coating to the S engines so had much less chance of bore scoring but bores scoping is wise. 

From cold many things can cause some sounds and it's hard to pinpoint. The SAI pumps are running and pulsing air into the exhaust when cold starting, the injection can sound more noise at cold and also the hydraulic valve lifters and running gear can also make noises as the engine warms and expansion takes place the noise should reduce and leave a gentle burble of a v8 engine with stable idle. 

If your not a diy person with spare cash and empty weekends I suggest you stay away. 

[vchris 0]

My 2008 CTT makes that noise especially when very cold outside but quiets in less than 2 minutes! I had the fear of cylinder scoring but after checking the noise comes from the valve lifters!!!!


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[Roxie 1]

Thanks to all!  Bigbusuki, by high mileage, what are you thinking?  I'm looking at 2005 with 69k and another with 97k.  Boroscoping is a good idea but I thought I read that the scoring was below the piston and only visible if you drop the oil pan?

 

The sound I'm hearing is a very slight and light knock on the drivers side middle of the row.  I know this is tough to answer without hearing, but wondered if it was something someone might explain.  I asked the dealer if they would do a pre-purchase inspection and they said no way.  I didn't know if this was just something they don't want to waste their time on or if they didn't want to be held responsible on an engine that seems to fail dependent upon the number of very cold starts?  CO winters aren't typically that cold, at least in Denver. 

I am a DIY guy, but not if I have to rebuild the engine.  Removing the engine alone seems like you need a special lift just to remove?  I do have available weekends and $$ within reason.  I'm good with $2-3k repairs, but not $20k on a car that is $10-20k to buy.  I'd rather spend the ~$35k on a newer 4.8L that doesn't have this problem, correct?  I do think the 1st gen body is better looking that any of the newer ones!  Thanks for everyone's comments!   

 

[Roxie 1]

Also, I've read the engine needs pulled to repair/replace the turbos on the 4.5L, is this the same on the 4.8L's?  Thanks.

[GSpence2 8]

Some very good advice here Roxie. As usual Messrs. Big and Weller are on point. I am currently having an expensive repair done on my '04 CTT for this very issue. It ain't cheap and is definitely not DIY for the uninitiated. If you have other options or choices of CTTs to choose from I would up my ante and look at maybe 955 Turbo S sans issues, or a 957 Turbo. Any money you may have saved by purchasing an inexpensive CTT with issues and the DIYing the repairs yourself, you can easily and probably equivalently put towards a newer CTT in better condition sans issues.

[ekstroemtj 25]

Check the plugs. Here you have one.

i have a first generation cayenne s which has a scored cylinder no. 6. i just replaced the plug because it wasnt working anymore. No wonder

[Ddavidoff 3]

Wow. That's crazy. How long did it take to get that bad?


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[ekstroemtj 25]

Actually i cant tell you exactly. I believe it was in there for some thousands. I dont now if it became so bad over the time or just in the last couple of weeks.   I will check the new one which i put in these days.  You will see how a plug looks after just some kilometers

[ekstroemtj 25]

On 2.1.2017 at 5:16 PM, Ddavidoff said:

Wow. That's crazy. How long did it take to get that bad?


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This is how the plug from the damaged cylinder looks like after several hundred kilometers. 

[Roxie 1]

To all:

 

Thanks for all of the replies!  Those plugs look terrible, where is the nice chocolate brown?  Good luck with the rebuild. 

 

I've listened to a 05 CTT for a second time and this time it was much colder here in CO.  I did a 10F cold start and the knock on the drivers side was even louder than when I heard it last when the temp. was in the 40F's.  I'm thinking this is an engine on its way out?  It only has 69k and they are asking $17k but I'm avoiding it like the plague.  I've heard multiples with this same side light knock.  I'll keep looking/listening...  I wish someone would post a youtube video of a cold start, after the engine drops to low idle to listen at a "good" engine with mileage between 70-150k miles.  Everything I've watched/listened to was already knocking badly. 

 

Thanks,

Frank 

[GSpence2 8]

Roxie/Frank - check this out. 

 

[Roxie 1]

Thanks for the video!  I have seen that one and it sounds very loud.  When I'm listening to the one here in CO it doesn't seem nearly as loud.  It can only be heard from up top meaning when I move down to the wheel well, I cannot hear it anymore.  The noise sounds like it is coming from under the drivers rocker cover, one of the middle 2 cylinders.  My concern is that this light knock would turn into the knock in the video. 

 

Thanks,

Frank

[GSpence2 8]

Here's a video of my own engine - currently being rebuilt after 130K. you'll notice that after the SAI pumps shut off the light knock becomes audible. From inside the car you don't hear it at all. Ambient temps were mid to high 30's at the time. What precipitated this finding was a low oil light following which I opened the hood to find oil everywhere and oil some oil in the coolant - looks like it just happened. Seems the oil cooler failed and the fan was spraying oil everywhere & I had no idea until the light came on. Add insult to injury, further tear down revealed the Y-pipe had not just cracked but was broken so major leak there and also the check valve adjacent to the AOS on the left bank was also cracked. Mind you no check engine light during any of this. At this point I told the tech to just change all the breather lines and vacuum lines while he was in there. Before doing this though he did pull the valve covers (I seem to change the gaskets every 2-years anyway) and no damage to the top end was found so definitely a bottom end issue. My tech advised he doubts it's a bearing issue because the engine still runs strong and compression was good all around when he checked, just the knock. I'll keep ya posted.

P1000116.wmv

Edited January 8, 2017 by GSpence2

[Roxie 1]

Ugh, that looks and sounds ugly.  Sorry for your pain.  Thanks for the video!  Did yours begin as most with ticking which then turned into knocking or due to the catastrophic nature of the failure did it go straight to a knock?

[GSpence2 8]

straight to knock. had not heard it prior to and no issues prior to the low oil light. 

 

[ekstroemtj 25]

My engine started with a very light ticking. Everybody thought a lifter noise or from injectors. Over time it developed to a very loud knocking. Sounds not nice. Like a loud old diesel engine

[ekstroemtj 25]

1 hour ago, GSpence2 said:

Here's a video of my own engine - currently being rebuilt after 130K. you'll notice that after the SAI pumps shut off the light knock becomes audible. From inside the car you don't hear it at all. Ambient temps were mid to high 30's at the time. What precipitated this finding was a low oil light following which I opened the hood to find oil everywhere and oil some oil in the coolant - looks like it just happened. Seems the oil cooler failed and the fan was spraying oil everywhere & I had no idea until the light came on. Add insult to injury, further tear down revealed the Y-pipe had not just cracked but was broken so major leak there and also the check valve adjacent to the AOS on the left bank was also cracked. Mind you now check engine light during any of this. At this point I told the tech to just change all the breather lines and vacuum lines while he was in there. Before doing this though he did pull the valve covers (I seem to change the gaskets every 2-years anyway) and no damage to the top end was found so definitely a bottom end issue. My tech advised he doubts it's a bearing issue because the engine still runs strong and compression was good all around when he checked, just the knock. I'll keep ya posted.

P1000116.wmv

 

 

Sound like my engine. I would say very clear to hear the piston slap.

 

[lewisweller 79]

See video hope it plays OK after compressing. This is my 2006 ctt with 122,000km. During the double head gaskets work 6 months ago at 112,000km I checked the cylinders for scores and Wear, there was none and no lip either where the piston ring finishes on the cylinder wall. So for all intents and purposes a good used engine I think for a audible comparison. I used a 10w40 semi synthetic oil on a short interval of 7,000km between changes. 

The engine was not completely cold coolant around 30oC and the ambient temperature is around 22oC. 

The tickiness I would say on the video pick up is more pronounced than it actually is in real life hearing it. 

You can just make out some changes in the ticks as the lifters start to expand and oil fully circulates and the injectors are adjusting as the car begins to warm which is all normal. 

 

videocompress-061-MOV_20170107_2057393.mp4

[Roxie 1]

So from super zoom to boom.  I'm sorry to hear and haven't heard about the oil coolers leaking until this conversation.  So losing oil and a similar knocking sound to the cylinder wall coating loss/piston slap sounds are similar.  One case the piston rings run dry and in another there's plenty of oil but lack of space tolerance leading to a high friction environment similar to running low on oil.  Am I getting this thought right or are all of them from low oil amounts/poor quality oils with regards to long usage times, i.e. 15-20k miles oil change intervals?  Does anyone know when Porsche changed the interval to 10k off hand?  Regardless, your expense will be a great one and I'm sure most feel your pain.  What's needed is a cheaper more readily available rebuild option other the company in the SE, 911 guy or super 6, can't remember theirs name but they seem to have it down on the repair or the dealer then I'd be less apt to purchase a vehicle with not enough metal in some instances, i.e. metal lines, even though its overall mass is great and off tolerances in others.  They gotta make money some how...        

[Roxie 1]

Thanks for the "good" engine comparison.  That engine sounds similar to the ones I've been listening to other than I hear more noise on the drivers sides, middle 2 cylinders.  I've heard that once warm they can get quiet early on before the oil burning near death time.  This is what I'm trying to distinguish.  Would I be buying an engine as you've described as normal or one that is early in the death cycle?  Thanks for the video though, It's the first I've seen that was considered normal and of no concern. 

[dpatel710 2]

4 hours ago, lewisweller said:

See video hope it plays OK after compressing. This is my 2006 ctt with 122,000km. During the double head gaskets work 6 months ago at 112,000km I checked the cylinders for scores and Wear, there was none and no lip either where the piston ring finishes on the cylinder wall. So for all intents and purposes a good used engine I think for a audible comparison. I used a 10w40 semi synthetic oil on a short interval of 7,000km between changes. 

The engine was not completely cold coolant around 30oC and the ambient temperature is around 22oC. 

The tickiness I would say on the video pick up is more pronounced than it actually is in real life hearing it. 

You can just make out some changes in the ticks as the lifters start to expand and oil fully circulates and the injectors are adjusting as the car begins to warm which is all normal. 

 

videocompress-061-MOV_20170107_2057393.mp4

 

 

Thanks for that video! There is a low end whine/whirring noise on my CTT that drove me nuts and eventually I was told it is normal. Sounds like you have it too. 

[GSpence2 8]

Okay so engine out and rebuild underway. On getting the engine out we realized the right side cat braided steel had separated so now it's new cats and an engine rebuild. I figured in for a penny inn for a pound. I've decided to install sport cats and a rear cat bypass set up. I'll keep ya posted. Oh almost forgot. The timing chain is stretched at least one guide is broken the seals on the aluminium coolant pipes are leaking as we're the breather lines and oil cooler.

[lewisweller 79]

2 hours ago, GSpence2 said:

Okay so engine out and rebuild underway. On getting the engine out we realized the right side cat braided steel had separated so now it's new cats and an engine rebuild. I figured in for a penny inn for a pound. I've decided to install sport cats and a rear cat bypass set up. I'll keep ya posted. Oh almost forgot. The timing chain is stretched at least one guide is broken the seals on the aluminium coolant pipes are leaking as we're the breather lines and oil cooler.

As your going the whole hog may I suggest two things, buy some 10dollar vac hoses and replace all the pipe from the turbo wastegates to the n75 valve, also buy some oring and change them for the turbo to IC and IC to Y pipe. Its so much less hassle and total cost will be less than 50dollars. Also I would replace the alternator, Aux belt tensioner and pulleys. Also check the SAI check valves at the back. They can be cleaned easy now, but when engine is refitted it's a real pain. 

I wish I had done all these job when my engine was out.