exact same symptoms as me! Thx for the input jumper.

 

Mine is a '99 C4 that had a Porsche replacement engine put in. The replacement engine scored the #6 cylinder at about 65k miles. Used year round in upstate NY. Only oil has been Mobil 1 0w-40 changed every 6k miles or so.

I've always done oil analysis reports. After last winter the oil analysis came back with high aluminum and silicon (cylinder walls) and the car developed a ticking noise.

 

P.S. I thought you guys would like seeing my last 3 oil analysis reports - aluminum and silicon have been increasing from the first sample I took 2 years ago.

Does anyone know what the piston skirt coating is made of? Note how copper went down - if that's part of the skirt coating, perhaps there wasn't any more to wear off!

 

Copper is bearing material.

 

Cylinder scoring - No
IMSB - Yes

 

Catch 22.....Store it during cold weather to save your cylinders only to lose your IMSB because of lack of use, Alex I'll take Murphy's Law for $200.

 

+996!

 

and another...

https://rennlist.com/forums/996-foru...l#post13072754

 

None on my Canadian 2004 c2. I change the oil every 6 months (3000 km or less) ow40 winter 5w40 warmer months. I don't have a cold thermostat but I am running Evans waterless coolant to eliminate localized boiling and hot spots.

 

and another, hasn't been confirmed, but I'm pretty confident listening to that motor....

https://rennlist.com/forums/996-forum/929414-help-engine-knocking-noise-w-video-and-audio.html#post13204050

 

2011: 106,000 km, scored #6. Oil usage had been creeping up over 2-3 years to the point where it was going through 1L per 1000kms. Oil and filter changes every 5K with Mobil 1 at the dealer.
Car was winter driven then, but garaged every night. Up the back straight at Mosport, blinking CEL came on and the car started running rough (yeah it was running on 5 cylinders!).
I elected to sell the engine as is to a tech at the dealer and buy a factory fresh X51 engine. I got a smoking deal and a 2 year Porsche warranty for a little less than what I was being quoted to rebuild the engine.
The new X51 hasn't consumed a drop of oil between changes but the car never sees extreme cold winter duty anymore. Very happy outcome.

 

not a 996 but close enough:

https://rennlist.com/forums/rennlist...confirmed.html

 

Also look at the Hartech theory. They believe that in the later 996 997 motors thr favtory used a head gasket that would fit either bank (to save money of course) but to do so the gasket had to have all the coolant cut outs the same size. Previous gasket had cut outs that had much bigger openings for 6 and 5 cylinders since they Were the furthest from wster pump and would overheat.

So the new gasket caused 6 to overheat and score.

 

https://rennlist.com/forums/996-foru...uild-help.html

 

https://rennlist.com/forums/996-foru...cylinders.html