vandal968

Yikes! I don't want to say it, but is that "the sound of great concern" for Cayenne owners?

c

95_993

What is puzzling is that the sound and smoke has gone away. Wants the tapping starts (piston slap from scored cylinder), I hadn't heard that it would go away.

Petza914

How low on oil would a motor like this with hydraulic lifters need to be for the lifter to not be able to properly pressurize and it be a lifter knock instead of something more serious - seems like more than a quart down, but I don't know which is why I'm asking. If the lifters aren't pressurizing right, maybe the valves aren't properly sealing and causing the smoke from combustion. It wouldn't be the first Cayenne V8 to experience bore scoring from cold climate usage, but might be the first DFI one I'm aware of with the others being the 955 motors. I can't remember what generation Eli's from Wheel Dynamics was when he posted about it here within the last year.

NelaK

I've been reading every post I can about scored cylinders and there are a lot of differing accounts. The only consistent thing seems to be that eventually the engines fail and the cylinders are badly scored.

Some things I've gathered though:
- In early stages the symptoms can be intermittent but they generally progress such that occasional smoking becomes constant smoking, and occasional tapping becomes constant and loud tapping.
- Compression/Leak down testing may confirm the issue or it may not. The damage isn't necessarily bad enough early on for compression to be significantly affected.
- Bore-scoping may confirm the issue or the damage at the early stages may be in areas where the camera can't see. Apparently the folks over at Flat6 have some way of inspecting from underneath the engine.

Other possible causes for the white smoke
- High humidity. The weather had about 50% humidity for the days in question.
- Coolant mixing in and getting burned. I'm monitoring the coolant levels but they seem okay. The engine oil doesn't appear milky or cloudy.
- Oil leaking through via the turbos. There's no abnormal noises that would suggest that.
- AOS diaphragm failure. No high pitched whine.

Other possible causes for the low oil
- I did drive the car in a 'spirited' manner a few days prior (responsibly on a private road of course). As per the owners manual the engine consumes oil by design. The level may not change until the car is driven aggressively at which point it will appear to have dropped suddenly. This doesn't explain the smoking or the noise though.
- Note: The oil was at the minimum mark when I saw it. I refilled to just a little below max.
- Oil leak. I checked all over the engine compartment and under the vehicle. Couldn't find any oil leaks or any other fluids leaking.

Other possible causes for the noise
- A tiny person got trapped inside the engine compartment and was trying to get out?

Coincidentally my extended warranty on the car runs out tomorrow so I've got the car booked in. I'm not sure if the mechanics will find anything at this point but I'd like to at least get the documentation started so later when things get worse, I can at least make a claim under the warranty.

Edit: Also going to send an oil sample off to Blackstone. I'm guessing they'll see any unusual wear in their tests.

oldskewel

Nice compilation of info on this issue. That will be great if you can get it covered under warranty. At least for tomorrow, hopefully you can get all the bore-scoring symptoms documented.

My paranoia made me inspect the heck out of my 2004 S before buying it, and I did an oil analysis too as the final step. Nothing out of the ordinary for Si or Al, so I'm clear. Documented it all in this thread:
https://rennlist.com/forums/cayenne-...e-ticking.html
in case you want to see another "normal" set of oil results, or listen to another engine video.

Petza914

what causes thus phenomenon is a number of short trips where the condensation that occurs in the engine as it warms up never gets evaporated off as the oil temp doesn't reach 212 F. This water then adds to what looks like the oil level. Once you take a long or spirited drive and evaporate off that water, it makes the oil level drop quickly because it wasn't really oil giving you that reading. Maybe the smoke you saw was actually water vapor or steam and the noise was from running with too little oil once the water vapor was eliminated by the spirited drive.

Great that you have a chance to catch something being wrong while under warranty though... usually things go bad the day after it expires, not the day before.

Also, when was the last time the Driver's side intercooler was emptied of condensed oil vapor? The crankcase vents back to this side of the intake and that vapor becomes oil in the bottom if the intercooler. It looks like a blown turbo, but isn't. If that hasn't been emptied in at least the last 20,000 miles, it can result in smoking.

cfiiman

I know you remove the turbo to intercooler pipe and empty it during an oil change, but is there a recommendation to actually remove the intercooler and drain it as well?

Petza914

The oil accumulates in the bottom of the intercooler itself. When upgrading my intercoolers to the FVD ones as part of my widebody build, I dumped almost 1/4 quart out of the intercooler, and the xat only has 28,000 miles on it so likely had never been done before by the PO or dealer during oil change services.

cfiiman

Interesting, I guess the front bumper would need to come off to get it out correct? Wish I would have known, I just had it off when I was rebuilding the AC system, man it would have been the time to do this but oh well.

Petza914

Probably or maybe feed a hose into it with a pump and just suck it out. My bumper was already off for the widebody conversion when I changed mine.

cfiiman

That's a great idea, I have an oil transfer pump I use when transferring waste oil from oil changes from my catch can to a dump container so I can use that. I'll take a look with my camera scope to see if I can see how much is in there as well the next time I do an oil change.

TomF

^^this^^

Without getting into the merits of one oil versus another, I have directly experienced (with two Cayenne Turbos and five 911s) that Mobil One seems to be more prone to moisture "absorption" (for lack of a better word) than other oils that I have tried. It leads to misleading oil level readings and as Petza914 stated, after a spirited drive a seemingly sudden drop in oil level. In reality, it is simply the water cooking off...

Cheers,
TomF

nodoors

I have the intercoolers off of my 955 turbo right now. I degreased both inside and out. I was pleasantly surprised to find that there was more oil in the charge hose leading to it than in the intercooler itself. There really was not much to speak of in mine, but I am religious about draining the hose every oil change.

OP, how often do you check your oil?

NelaK

Weirdly enough - while I'm not afraid to get my hands dirty with my other cars, the Cayenne has been under warranty until today so I've always been very hands off and let the Porsche dealership handle every aspect of its care. I'm going to assume it was done at the last oil change by the dealership about 6 months ago.

Its currently at the mechanic's for the sake of taking advantage of the last day of warranty even though I'm assuming they won't find anything since they are neither Porsche specialists nor have dealt with this sort of thing before.

Once I get it back, I'll start looking into it more thoroughly myself but at least I'll have a shop repair on record which I can point to and say was misdiagnosed or didn't resolve the problem.

Edit: After calling and checking with the dealership it seems they don't drain the oil from the charge hose unless there is a complaint about smoking. The service adviser also didn't seem at all concerned about the symptoms my car was showing and according to them its completely normal after the car has been driven hard.

nodoors - I tend to check it at every fill up or every other fill up depending on if I'm in a rush or not. That tends to work out to about once a month or once every couple months.

NelaK

Just an update.

- Bore scoping revealed nothing.
- Compression test had all the cylinders nearly identical +/- 2 PSI
- Spark plugs looked pristine. Almost -too- pristine? I recall hearing combusting coolant can do that.

Next step is to rule out any head gasket issues which seem pretty unlikely but might as well be thorough. Also still have to check the intercooler charge piping.

Also sending off an oil sample to Blackstone labs.

I think the oil sample is probably the only somewhat reliable test. All the others aren't conclusive one way or the other. On that note - it should probably be a requirement when owning a Cayenne to get the oil sample analysis either every oil change or every other oil change.