I've only had my high mileage (123,000) 06' CTTS for a few months and only put just over 1000 miles on it. I now have tapping that was intermittent and seems pretty regular. I haven't done a compression reading but have checked the plugs on the side thats making noise and they are all normal with no oil fouling and oil usage seems ok. I do have a P0011 on Bank 1, but the noise is on bank 2.

I'm wondering (dreading) if this is a bore scoring noise, what do you think?

 

I don't know, but I had been thinking about analyzing the sound like you've given us there. I made a video when doing my own PPI before getting my 2004 S late last year:
https://rennlist.com/forums/cayenne-...l#post14675228
(it's still running)

Here's the thought - it may be wrong, but let me know if it is ...

The bore scoring would be a cylinder issue, with a frequency at the engine RPM = rate of crankshaft revolution.

Many other tapping sounds that are NOT related to bore scoring are related to stuff going on up at the cams, which would have a frequency at half the engine RPM.

So then if this is right, you should be able to check to see if the tapping is at engine RPM (e.g., 600 RPM = 10 per second) or half that (5 per second) to rule in or out any bore scoring issues.

What do you think?

 

mine seems a lot louder than yours! Not sure about your theory as on my sound clip it took 3 seconds to count 10 taps.

 

Sounds like hydraulic lifters. Add 2 bottles Ceratec. Bore scoring makes a louder, "clacking" sound.

 

Sound intensity will vary a lot based on where you're measuring from, but yes, mine is pretty quiet by comparison.

Most things in the engine will either be at crank frequency (engine RPM) or half that (cam frequency). My numbers chose an easy-to-calculate engine RPM of 600. Maybe your idle was a little lower (e.g., 400 RPM would give your reported 10 taps in 3 seconds). But your numbers point more to the cams than the crank, which would be good news for you.

Still hoping for input on the validity of this thinking.

 

Dilberto, I know you have bore scoring hence the Cera Tec, if I don't have scoring I'm going to try Liquid Moly Hydraulic Lifter Additive 2770 first.

oldskewel, I'll run the car up tomorrow evening and see what the idle is. What you say makes sense, but I'm far from being able to validate.

 

Doubt that is lifters. That's knock or possibly an exhaust leak.
As far as the lifter additive, no thanks.Distillates (petroleum), solvent-dewaxed heavy paraffinic
The Ceratec is the real deal, stuff works. It is the finest additive Lubri-moly makes. On a side note, I put it in my front and rear diffs and it made a huge difference in rolling resistance both on and off the ground. I was very impressed. Be aware that it will separate and fall out of the oil when fresh. It's thick and has a lot of solids in it irregardless of whether the particle size is nano or not. I feel like what people don't talk about is that it needs to be diluted and mixed into preferably the whole 9 quarts of oil on a change and run to full operating temperature immediatly and preferably as long as possible. Several hours of run time would be a good start. Of course this is just my opinion.

 

The idle speed is 580 +/- 50. This is not adjustable nor variable. This is what the ecu commands irregardless of load or enviroment on closed loop idle.(fully warm oil and water) This applies to every Cayenne 4.5 Cayenne v8 in the world unless you are not on the factory ecu tune. Even then I cant see why a tuner would change this.

 

A buddy just picked up one of these cheap little cameras that would easily go down a spark plug hole. Should provide a pretty good perspective for bore scoring. They have a mirror attachment that should work like a champ.


I'm not recommending this one specifically, its just an example- there are lots of them. Need to research to see if there's any difference besides price. I'll try to borrow his and see how it works.

 

Great price.. I ordered one. Will report on how good it is..

 

I have a boroscope, but I've not used it to check for scoring yet as my plugs aren't fouled and so I feel its pretty unlikely to show significant scoring, but I will do this when I change the plugs.
I got the Liquid Moly Hydraulic Lifter Additive 2770 today and added it to the oil, the engine was silent for several minutes idling and felt great,but after going for a 10 mile drive the engine is still tapping but quieter.
I feel it is a valve train issue as when you rev the car the clatter is slightly behind the revs, OTOH why was it actually silent for a few minutes when the LM was added?
I'll drive it tomorrow to see if it improves.

 

The reason I said no thanks to the LM lifter additive is because there is no magic cure for sticky lifters while they are in the engine and a heavy detergent like that is likely to do more harm than good.

 

My Cayenne has a full history so its not been neglected, so I don't think there is too much risk. I thought twice, but its worked for a lot of people (if not everyone), it's a reputable brand, and it says it can stay in the oil until the next oil change. If it was runny like neat fuel I wouldn't have added it, but its thick any very slippery so I did. The LM website says it does not affect oil viscosity.

 

I've driven a few hundred miles with the Liquid Moly Hydraulic Lifter Additive 2770 in the engine oil and I doubted it would do anything much, but it has actually substantially reduced the tapping noise. I now struggle to hear it resting my ear on the bonnet over that bank, rather than it sounding awful from several feet (or more) away. Whilst I appreciate its not a 100% fix its certainly good enough for me to decide to keep the car.
Interestingly enough it seems to have resolved the P0011 (Camshaft Position A - Timing Over-Advanced or System Performance Bank 1), that I would get with monotonous regularity.

 

Great news. Thanks for following up.