Oil Filter Inspection

[qcrazy]

Picked this up with my 996. This is a must with the 996, figure it made some since on these cars with the oil screen issues.

For those that haven't done this. You take your old oil filter and a sharp knife and cut it open. Then you can pull the pleats apart and see what type of debris the filter is catching. Gives you a little insight into your engine for 5 minutes of work.

First cut the outside, all the way around. Takes a little force as there is a metal mesh in there...push under control...keep legs/arms clear:
20210711_163542.jpg

Then cut across the middle so you can open it up:
20210711_163722.jpg

When done it will look like this:
20210711_164034.jpg

The 4.0T is an outside-in filter. So the debris will be caught on the OUTSIDE of the filter. This is my filter after I did my turbo swap from the failure. I ran this oil a little bit after the new turbos before changing oil This oil had about 2500 miles on it, a touch over a year old. Here is what I got...
20210711_165556.jpg

If you look at the pic close, we got some black debris and just a few shiny pieces. Here I highlighted a couple of the shiny pieces.
20210730_223017.jpg

This is aluminum, just showing engine wear. Typical stuff here. Nothing that is worrying, not many pieces, pretty small. Looks good.

The black stuff I am not sure about. If it was my 996 I would say it was plastic from the cam guides. But in the 4.0T, it doesn't appear they have black cam guides, so that likely isn't it. There is not that much of it. But enough. Here is a closer view...
20210730_223728.jpg

Pretty small stuff. Looks a bit like the gunk in/around the PCV in these cars. Also looks a lot like the stuff some people find in their oil screens. At this point I am going to call it PCV stuff, unless someone else has a better idea. We'll see if I just stirred a bunch up swapping the turbos...find out when I check on the next oil change.

Anyone changing oil, feel free to cut your filters open and post your pics. It would be good to get a thread going to see what kind of debris people are catching in these engines.

[gk1]

I took your initiative and cut mine too.
5k miles 6 months 50k miles on car all original Stage1. (5k OCI with 2 extra at 6 month covid intervals)
It looks the same as yours but with IMO fewer black specks.
I did notice my glue rings around the outside were completely black and not as translucent as yours, but maybe that is because of more miles or different glue types used when the filters are made?
I am also curious where the black specs are coming from they just look like dirt/carbon to me. Since this is the first filter I've cut open on any car I don't know what is/is not normal, but I have no reason to believe there is anything wrong with my car. Turbos had no play just 15k miles ago and I have no reason to suspect they are failing.

Also I'm wondering if the glue is just there to hold the media in place while the endcaps are installed during manufacturing, they don't seem to serve much function.

[qcrazy]

I appreciate you taking a look. I was hoping my debris was from having everything opened up, but maybe not. Maybe the amount?

Agree with the dirt/carbon comment. In my experience this debris is a bit abnormal. And in my case it seems very abnormal based on the minimal mileage on my oil. Carbon is typically a result of blow-by/PCV "stuff".

Typical to see metal specks and plastic pieces, but this is a bit different. Larger particles are worse than smaller particles. Size-wise these are okay I guess.

Probably right on the glue rings, likely just for assembly.

[gk1]

These seem like apt descriptions from a Cessna site.

https://www.cessnaflyer.org/maintena...in-my-oil.html

Carbon
Carbon is usually always present in the filter element. Some carbon is normal, but large amounts of carbon in the filter/screen are usually the result of excessive blow-by past the rings. Oil that rapidly turns black soon after an oil change is also an indication of blow-by.
Carbon flakes are black and can appear shiny, but are easily distinguishable from metal. Carbon flakes found in an oil filter/screen can effortlessly be broken apart with a small pick or even between fingernails. Metal flakes will remain intact.

Aluminum or bronze
Aluminum shavings or flakes are occasionally found in filters and are almost always the result of wear from a piston pin plug. The piston pins themselves are free floating, and the plugs installed on each end are made of a fairly soft metal like aluminum or bronze, so that as the piston pin plugs occasionally come into contact with the cylinder wall, they wear without damaging the cylinder barrel. The piston pin plugs are designed to wear slightly, and will sometimes wear a little then stop once they are no longer contacting the cylinder wall.

Brass
Brass-colored nonferrous slivers are usually generated from a wearing rocker arm bushing, or possibly on some engines, a starter adapter bushing. A tiny sliver or two is generally not a big deal, but regular occurrences or large amounts would merit finding out where it is coming from and fixing it.
(I'd assume turbo journal bearings fall into this category too.)

Magnetic particles
The presence of magnetic particles can be detected with a mechanic’s magnet. Sweeping the magnet across all the pleats of the element or towel/filter, just above the surface, will generally pull and reveal most of the magnetic debris.

Also fwiw I run a full bottle of Redline SI-1 the tank before an oil change so I may dislodge more carbon and crap from the pistons that blows-by into the oil than normal.

[Alabama]

Also fwiw I run a full bottle of Redline SI-1 the tank before an oil change so I may dislodge more carbon and crap from the pistons that blows-by into the oil than normal.

That seems logical. Not all the dislodged carbon burns up in the cylinder.

[Optimus247]

Left over debris getting rinsed out ...? You did have a turbo failure ...

Was the oil pan dropped and completely washed ...??

[gk1]

I feel like part of the takeaway from this exercise is that with or without turbo failure the 4.0T is a dirty engine and Audi's recommended OCI should never have applied to the 4.0T in the first place.
The additives in the oil may not wear out, but it generates so much filth that it demands shorter oil and filter change intervals but in its haste to have all their engines conform to those long change intervals they put in the dreaded turbo oil screen instead to catch any extra debris making it past the main filter, which created the issue of the screen clogging.
At least that is my 2 cents. We'll see how I do in another 25k miles if I keep it that long.

[gk1]

Also I flushed out some of the debris into a glass measuring cup and ran a strong magnet over it. They are definitely not magnetic...not really a surprise just a note.
Also they appear to break up rather easily leading me to believe it is carbon as per the description above.
I've managed to wash some into a lab filter and may check them out more tomorrow once the filter drains. Maybe see how they react to a drop of SI-1 or other chemicals.

[qcrazy]

I agree with gk1's thoughts. This seems to be a dirty burning engine. Or perhaps just has an inefficient PCV design.

Yes, I had a turbo failure on this filter. But there is no brass in the filter as I didn't let the failure progress to the journal bearings or thrust bearings.

Yes, I pulled everything up top apart which could have stirred up more carbon (I hope that is the case). gk1 also did a treatment which could have done the same.

No, I didn't drop the pan as there was no reason too. My journal bearings were fine so no brass was expected (as confirmed in the filter) and there is nothing with a turbo failure that should inherently increase carbon.

This is just the first filter I cut open on this car. I will do others and that will eventually give us a more complete picture.

I am hoping others will join in on this. The more people that open their filters the clearer picture we'll be able to get on this engine.

For comparison this is from my 996...
20201004_143732.jpg
Not the greatest picture. But both my 996 and S6 are around 90k miles. This filter had about 2k miles on it (compared to 2500 on the S6). There was similar aluminum as in the S6, just didn't come out in the picture. You can clearly see there are less black specks in the 996 filter. And almost all of the black specks you see are not carbon. The black in this filter are plastic from the cam chain guides. There are only a few specs that are actual carbon in the 996. Hence, the interest over the carbon in my S6 filter.

I truly hope I just stirred a bunch of carbon/dirt up in the turbo swap. But I don't know that yet. I am glad that gk1 had less carbon then I did.

[gk1]

This is what the debris looks like out of the filter.
Clearly carbon, it is easily crushed/smeared like pencil lead.

Found this website too.
Would be interesting to see their analysis.
https://www.oillab.com/filter-analysis

[qcrazy]

Adding another data point to this thread. This is NOT from an S6 though. This is from my B9 S4:
20210918_104455.jpg
There are no black specs in this filter at all. No carbon, no plastic. There is a bit more metal than what I would want to see. Not alarming, but something for me to keep an eye on. Car has 40k miles. Filter has about 8k miles.

I am posting this here, as I found it interesting that this filter (from another turbo Audi) had zero carbon. I was expecting to see some, but I could not find any. Makes me wonder about the PCV in the 4.0T.

[gk1]

Adding another data point to this thread. This is NOT from an S6 though. This is from my B9 S4:
20210918_104455.jpg
There are no black specs in this filter at all. No carbon, no plastic. There is a bit more metal than what I would want to see. Not alarming, but something for me to keep an eye on. Car has 40k miles. Filter has about 8k miles.

I am posting this here, as I found it interesting that this filter (from another turbo Audi) had zero carbon. I was expecting to see some, but I could not find any. Makes me wonder about the PCV in the 4.0T.

Interesting. Good point about the pcv and carbon maybe. I'll have to try cutting my MKI SQ5 filter when it is time for a change. Using the same exact oil in that as the S6.

[gk1]

I cut the filter on my 2014 MKI SQ5 with 85k miles. Same OCI as the S6 5k and same oil used in both. Motul Specific and now Motul X-Clean 5w-40.
I see very similar to your B9 S4. More metal (not alarming) but no black specks.
So at least for me I can rule out oil type as the source of the specks. Also for the most part we use the same fueling stations for both cars, so IMO that is out, and I also did a full SI-1 treatment in the tank prior to the oil change on the SQ5 as well.
If the PCV/oil separator is somehow dropping carbon out of the system into the oil, I just don't understand how. How can the PCV/oil separator be that much different, and it what way, than either the SQ5 or your S4?
If it is carbon it has to come from fuel right? Is the 4.0T just a naturally rich running motor? Does the 4.0T have worse piston ring seal than two different 3.0T variants?
Perhaps does CoD have anything to do with it? With the injectors off and valves closed does the trapped exhaust gasses in those pistons force carbon deposits into the oil?
I mean I can still achieve a 29.5mpg calculated mostly highway commute at 80mph so I have my doubts anything is wrong with my particular 4.0T at this moment. (I can even get over 30 in cool weather if I drive slower.)

[qcrazy]

The 4.0T has a few oddities:

1) It has these long blow-by passages built into the intake. This is weird, these are normally really short, and typically machined into the heads. Why Audi made these so long, I don't know. But this is a great place for the blow-by to collect and settle out.

2) The course oil separator is wierd too. The blow-by follows this long path to the PCV, then immediately drops out the course oil and drains this back into the pan. When you pull the PCV this drain is where you see all the thick build-up. Typically you don't collect the course oil. Usually they just slow down the collection of the gasses, causing the flow to stagnate and drop back through the crankcase by gravity.

3) The intake temps don't help for good combustion either. I took my B9 S4 out and did similar runs to what I have been doing on my C7. On the B9 my temps maxed out at 9F above ambient. I ran it twice because I thought it was an error...it was not. On the 4.0T you can't even get 9F while crusing. And on my pulls I run somewhere between 60 to 90F above ambient on the 4.0T.

I would be curious to see what the filter looks like on a stock 4.0T. Where boost would be more reasonable and intake temps would still be in what Audi designed.

Would that filter still have a bunch of carbon? It seems like it would from the turbo failures... but would it?

[gk1]

Good points.

They way I'm driving I should just switch to stock mode for my next oil change. It should take me less than 4 months to hit 5k miles, but it will be winter months Nov to March which could be a factor too.

[gk1]

Did another 5k change not long ago. (Full bottle of SI-1 the tank prior again.)
Same results, some black soft carbon particles in the filter. Seemed like there was less of them but I didn't do any scientific measurements. (Maybe 5 large enough for me to see.)
I also didn't switch to stock mode, so same tune as the previous change just cooler ambient temps.
Stats:
Last oil change - averaged 46 MPH 48 MPD 19.3 MPG 60% Hwy miles
This oil change - averaged 52 MPH 57 MPD 20.4 MPG 80% Hwy miles
So more highway driving at higher speeds this time around.
This was also the 26th tank of fuel and only the 2nd oil change since the LPFP was replaced.

[qcrazy]

Good to see less carbon! I won't change my oil again until Spring.

My next change will be the first change without a blown turbo in between. But I also did a lot of pulls on the oil, without much for road trips in there.

[WhiteDiamond]

Did this process several times after my turbo fail. I was very "lucky" to get a TON of the turbo bearing material into the oil, so I inspected the first 4 filters very carefully. The 5th showed ok, so haven't been doing this lately, but very helpful if you suspect anything.

[qcrazy]

Updating this post again. I just did another oil change. This filter has about 4400 miles (compared to 2500 miles in the original post). This oil was used on my cooling thread, so those 4400 miles have a lot of pulls on them.

This filter looks really similar to my last filter. Maybe a bit more carbon, but not a lot. More would be expected since this does have a few more miles...

20220513_133159.jpg
20220514_164717.jpg

All in all, filter looks pretty good considering. (Stage 4 S6, running TS1's). I did send out for an oil analysis on this change and will update when that arrives. Expecting fuel contamination...but we'll see.

[Botbasher]

I would be curious to see what the filter looks like on a stock 4.0T. Where boost would be more reasonable and intake temps would still be in what Audi designed.

I save all my old filters and such. I'll pull mine apart and tell you what I see. 2014 S6 completely stock 103k when purchased. Serviced by Audi till 96k

Cheers,

KS

[qcrazy]

Here is my oil analysis for the filter above. This is oil post-turbo failure, so should be little if any cross-over. Not sure what to make of the silver. TS1 bearings breaking in? A little surprised about the "no fuel" in the oil...I was expecting some.
0522OilSnipRed.jpg