I have 104,000 miles on my 2005 CTT now. I have always had consumption around 1 qt in 1000 miles since owning it with 43,000 miles.
I am getting the puff of oil smoke on start up, for about 1-2 seconds then gone, mostly after a warm start up.
Ive had some other drivability issues, so was scoping my cylinders.
i found obvious leaking of oil from the exhaust valves only, not the intake valves, clearly running/dripping diwn the walls. Likely Exhaust only, cause they are the hotter side, harder on the seals, plus lowest in the head so oil pools by them.
plus, cyl 3,4 and 7, 8 are worse, cause the engine leans back, again more pooling due to gravity.
Not, orientation in these pics is top of pic is down the cylinder, bottom of pic is up or valve side of cylinder, due to my crappy boroscope and mirror attachment



Is there a high mileage oil i can use to help swell the valve seals up? I haven't found a euro 5w40, usually I only see 5w30. Can i run that an oci or 2?

Who has done valve seals? Is it an engine out or heads off job?

 

Porsche say in the owners manual that 5w50 is fine so I'd use a good one like Mobil 1 or Liqui Moly Molygen and that might help keep consumption down a bit. If you want to swell up the valve seals, Liqui Moly has their super leichtlauf oil which does this although I think it only comes as a 10w40. You can just get their oil resealer additive though which does the same thing.

Apparently the exhaust valve guides in these engines tend to wear quite substantially, and I've seen a number of cases of burned exhaust valves because of this. Some have failed really early on but others never seem to have the issue. Life is too short to stress on it though, so just use a good oil and enjoy the car.

 

I agree with this. You could try a bottle of some sort of seal conditioner, but you might just have to live with it assuming it's not causing your other issues.

 

Not stressing too much, but im starting to wonder if its what's affecting my driveability. Im still checlking all the other typical things, coils, vac leaks etc.
i ordered 2 cans pf LM Oil Saver so will give those a tey with my euro 5w40.
i did see that, 5w50 on the owners manual too. Ill try that my next oil change.

What would the sypmtoms of a burnt valve be?

Thanks guys. Asking more to learn and understand this situation since I dont see too many discussions about valve leaks here.

 

What volume of oil are you normally consuming?

 

Since you were using 0w-40 before maybe just step up to 10w-40.

 

Zero compression in that cylinder which results in a 7 cylinder engine. I replaced the engine in my CTTS because of a burnt exhaust valve in the right rear cylinder.

 

My 2¢ after reading your other thread:

While one bank looks bad, most of your issues seem to be with cylinder 4. The plug looks horrible after a few miles and you have a crazy amount of misfires reported.

A bad coil will cause fuel fouling, and a modern ECU should shut down fuel to that cylinder. The photos you posted look like oil fouling to me. If you let the plugs sit for a day, did they seem to dry out or stay wet?
Fuel pump pressure will affect the entire engine, not just one cylinder. If it's low, you'll fuel starve the cylinders, not fuel soak plug(s) within a few miles.
Provided you have a healthy alternator, I don't see how an old battery can affect the fuel or ignition system. If the alternator failed and you were running on battery power, the ECU would shut down unnecessary systems to keep power to the fuel and ignition systems. Even if dropped to 10 volts leaving your stranded, it's still unlikely you'd have any fuel fouling.
Plugged cats will give you poor performance and won't single out one cylinder. Also, you can bet there will be dash service warnings reported long before you even begin to notice butt dyno performance, let alone drastic driving issues.
Valve stem seals wear out evenly over time. A sign of worn out valve stem seals is that puff of blue puff of smoke at start up you mentioned. But even with moderately worn seals, the plugs will typically clean up within a few miles after that initial start.

IMO, you have some type of failure that isn't going to be cured with an oil additive.
No offense, but your camera is of no help , it reminds me of a poster you'd see at an eye doctor's office showing how an old person sees through cataracts.

Personally, I'd start with a decent camera to check for bore scoring, because unfortunately your turbo isn't immune. The theories on how it rarely happens on turbo engines just gives false hope. The survey Don set up was interesting when you consider how many more NA Cayennes were built vs. turbos...it wouldn't surprise me if there have been more '08 turbos with engine scoring that all other years of NA engines combined. And speculations from rebuilders posted back in 2012 when the problem was really starting to rear its ugly head doesn't mean much these days. A simple Google or YouTube search with "Cayenne turbo" (in quotes) along with words like scoring, ticking, lifter noise, piston slap will make one cringe.

On the bright side, I've never read a single bore scoring post that didn't have hundreds or miles worth of loud ticking before plug fouling became an issue. I'm betting yours comes up clean, and if it does, invest in a compression tester and leak down tester and start with #4. I think the best outcome is drastic failure of a few valve stem seals. If the Cayenne is like other engines I've worked on, they can be replaced without removing the head.

 

I might have the injectors cleaned and tested for leakage, if you haven't done this yet. That's about $150 from Hurst Injector Service to do all 8. My car had a leaky injector which happened to be on the cylinder with the burnt exhaust valve. Perhaps a coincidence? Leaky injector will dilute any stray oil with gas and spread the oil out all over.

 

1qt per 1000-1200 miles after a change, then it starts declining as the oil ages and assuming gets thinner with use, last top off prior to a change around 3000-4000 miles close to 1qt per 700 miles.
its been like this since ive owned it with 43,000 miles, now 105,000.

 

I finally did a compression test, not sure i had that update on the other post when you guys all read it.
120-130 range, cylindee 4 and 8 where I have the cumulative 200 or so misfires, compared to all other cylinders at 20-30 misfire counts where 125 for 4 and 130 for 8. On the higher end/ mid point, not low side.
im working on a better scope.

Yes, agree, I don't feel turbos are immune, actually with the boost, im concerned even more.

I just did get some codes finally, my other post has the updates. In short, vacuum booster pump is bad, blowing #12 fuse, then car no longer makes fuel trim adjustments, all readings go to zero and stay there. I Unplugged the booster till the new one comes in, fuse doesnt blow now and trims working again.

If i pump the brakes now with the boost pump failing/failed or disconnected, I get a sucking sound coming from under the intake manifold after a few pumps, then it goes away after stopping pumping There is the brake booster line that 90 degrees down into the back of the intake manifold, since the pump isnt helping/working, are the brakes pulling too much vac from the back of the engine posdible messing up the air into the back 2 cylinders 4 and 8?
i smoke the line from the brake booster gong into the back of the intake, no leaks.