Disappearing oil in 02 C4S

I've had my 02 C4s for about a month now. I've put 1000 miles on it, it is my daily driver. Best commute I've ever had, no matter what the traffic. The other day I actually waited for the computer oil diagnostic to run. It reported me as actually below low. So i checked the dipstick and that looked to be the case. I put a quart of mobil1 0W-40 in. Didn't notice anything unusual in and around the filler tube. Drove 10 miles and ran the diagnostic again. Still below low. Added another quart. Still below low. Added another quart and then it was 1 bar above low. Added another and it was at full. I actually was doing this in half quart increments (per my manual) until I got impatient with it still being below low. I drove the car for several days since then. It is driving great, sounds great. I have no white smioke at start up (only have had that and a little white goo in the tube when I haven't driven it much and run the engine for short durations so it never warms up - which is just when I need to move it around the driveway). The oil pressure when I first reached full on the oil (stupidly I never confirmed this level with the dipstick) was more or less pegged at 5bar if I was doing anything other than idling. Now a few days later is more like 2 bar at idle and going up to 3-5 bar depending on the rpms. I checked the oil. The dipstick and diagnostic both seem to confirm that I am at low again. I have no oil leaks that I can see. There is no smoke ever that I can see. My driver side tailpipe is sooty (black). So is it possible to burn almost 4 quarts of oil in a week (over ~300 miles of driving at local to highway speeds) and not see big clouds of smoke? Is something else going on? I get the tailpipe points to oil being burned in the engine, but this seems alot. What I'm doing and going to do: 1) I've wiped tailpipe clean to see how quickly it soots up again 2) Remove the filler cap at idle and check for a vacuum pull to see if this is an AOS related problem 3) inquired locally about voodoo Other suggestions? Should I try bumping up to 5W oil from 0W? Thanks. UPDATE 6-18-2017 1) I added 1.5 quarts of Mobil 1 0W-40. This morning at a cold start, later fully warmed up after filling up with gas, and 6 hours after last driving it the dipstick and electronic meter both read full. Car continues to drive well and sounds good as far as I can tell. 2) I did a cursory check on the AOS by removing the oil fill cap. I don't yet have any type of manometer. With the engine fully warmed up and at idle, the cap came off without much effort. There was definitely a vacuum. Covering it with my hand or not did not alter the idle at all. With the engine sitting for 6 hours and then starting it and repeating this test there was about the same vacuum (simply qualitatively determined by how much I felt pulling on my hand, so not quantitatively) but with my hand off the filler tube so it was open the idle got rough. Not to the point it stalled but definitely changed. The coolant tank is roughly just under full, as it has been since the indy shop topped it off 3 weeks ago during an inspection. Still the only smoke I see is when starting a cold engine after it was last run and shut down cold (as in I ran it to move it around the driveway). There is no noticeable smoke during driving or starting the engine while warm or if it was last shut down warm after a drive. In parallel to tracking my oil consumption I'm going to build/buy a manometer to quantify the vacuum. Since the AOS seems to fail at a high rate and is somewhat time consuming to replace it seems helpful to measure this. Is any change in idle indicative of an AOS failure? Next steps this week: a) Will continue to monitor gas mileage, oil consumption vs mileage, coolant level, and amount of soot on tailpipes (I wiped these clean to provide a baseline) over the next 2-3 weeks. b) I expect to be able to change both the oil and filter later this week. At this point I'll also install the the magnetic oil plug I ordered. c) Build/buy a manometer and quantify the vacuum pressure.

These cars go through oil, but 4qts is beyond excessive. If I were you I would do an oil change and start over. Try to measure the oil that comes out. Give you a blank slate to start from.

Good idea on voodoo! Now for the issue. You are doing the right thing. You need to establish a baseline for oil consumption versus mileage. Remember the sump/engine contains about 10 QT's of oil. Check your oil level on the dipstick when the engine is stone cold, meaning, like in the morning before you fire it up. Then do this consistently for several days. Fill it back up to full if it drops and note your mileage. That should give you some good baseline data for oil consumption versus mileage. Depending on the weather temps where you are, going to a 5W could help. You do not want to even begin to think about why the engine consumes to much oil - scored bores, piston rings, valve stems and seats, and so on. What you want to do right now is see how much oil is consumed and whether that is within a tolerable range. Also note that I said to use the dipstick. The oil level guage is not that accurate, readings can vary depending on a lot of different factors. Use the dipstick for accuracy. The oil pressure sounds about right, however, the oil pressure sender unit in our cars are notorious for erroneous readings, especially when old. Might consider replacing it.

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So rather than waiting the 10 seconds for the oil level monitor to report you simply ignored it for x amount of time and it was a full 4 low? Kind of irresponsible if you ask me. Hopefully nothing was damaged by the excessively low oil level. The engine will consume "some" oil but they are all over the place as far as how much. For instance my 03 C4S would use 1/2 quart in 5,000 km of driving at the most.

Do you know, really know, if you started with a full charge of oil? I think each mark on the digital gauge is something like 6.7 oz. so down one bar is not tragic. I swear I read in the owners manual that 1 quart in 600 miles or 1000km can be considered normal, but I can't find it right now. I agree 4 quarts would be excessive. Recommendation on checking oil is stone cold as mentioned above, 24 hours if possible. Trust the stick and make sure it is fully seated against stop when doing measurement. I've caught myself not fully seating stick and come up with short readings. Just make sure...

Check your coolant tank to make sure it's not going in there...

Also make sure you're on a level surface when checking the electronic gauge - it's very susceptible to false readings. The car has to sit for twenty minutes or so when warm to get any sort of reading - and it will still read somewhat low (it takes awhile for the oil to drain out of the heads and back to the sump). Accurate readings are taken after an overnight sit - and once again, on a level surface. Good luck

I cannot get consistent measurements from the computer at all. Even taken same in the same level spot, warm engine and same timed since shutdown. Up and own swings of 4 to 5 squares, no consistency. I have given up looking at the computer completely and just use dipstick on a warm engine. I am burning a QT per 2000miles. I would not add oil based on computer alone. Make sure dipstick agrees if something doesnt seem right. Mine is 02 C2.

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In your case it reads like the oil level sensor is broken. This sensor consists of a loop of wire the loop runs down inside a small diameter plastic tube that extends down into the oil sump. The loop of wire is bare. To take a measurement a known amount of voltage is run through the wire for a fixed amount of time and the voltage level that makes it through the wire is measured and this correlates of where the level is. The voltage level is affected by how much of the bare wire is submerged in the oil. If the little plastic hook that holds the wire at the bottom of the plastic tube fails the loop of wire can move about and because it is not kept in proper position the reading will vary.

The computer on mine is rarely accurate. I use the dipstick. It's F-ING INSANE that new Porsches do not have oil dipsticks because their sensor systems don't work.

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It is possible to burn 4 quarts of oil in ~300 miles but I would have to believe you would notice the engine smoking. Occassionally I observe a vehicle taking off from a stop light, or just going down the road/freeway and oil smoke trailing behind the vehicle. While it is clear the engine is burning oil I strongly suspect it is not burning 4 quarts in 300 miles. Right now you do not know for sure just how much oil is in the engine. My recommendation would be to have the engine oil properly drained and refilled with a known and correct quantity of oil appropriate for your car and at this time the tech would then check the electronic oil level sensor and system is working properly. Ask him to confirm the oil dipstick also reads correctly. You want to know the engine has the right amount of oil and that both the electronic and dipstick measurement systems are reporting oil levels that are in agreement with each other and just as important in agreement with how much oil is actually in the engine. Then drive the car as you normally do and keep track of the oil level. Be very consistent in when and how you check this. The car wants to be very level. A bit up or down at either end can affect my Boxster's oil level reading by 2 bars. With the car tilted sideways the level varies even more. I check my Boxster's oil both dead cold -- with the car having sat overnight unused -- and fully up to temperature. Often this oil level check is made when I stop and fill up the gas tank. The engine is hot, fully warmed up, and the gas station drive is quite level. After filling the tank the oil level reading count down starts at 5 seconds. Check the oil level and monitor the change in the level. If you see the level dropping as you add miles then there's something going on. There's not much you can do on your driveway. I'd not bother trying a different oil. Really if the engine is using oil at the rate you suspect (but which I doubt is actually occurring) no oil will help and you don't want to run the wrong oil and possibly damange the engine internals when the heavy oil consumption might not be that serious of a problem, though obviously its cause should be found and fixed ASAP. If you see the level varying -- this is assuming you use the electronic oil level system -- then what is probably going on is the electronic oil level sensor has suffered a problem (a loop of wire is loose and moves about and this affects oil level reading) -- and this needs to be addressed. Probably by having the oil level sensor replaced.

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Ironically I brought it to my INDY to checkout and ofcourse it works perfect infront of them. I have tried taking readings in a few different places (gas stations, most level places I can find) and it if I take enough readings it will show inconsistent results. It seems to work more than it doesn't...but overall I do not trust it. I just check the stick every week, before a cold morning start and up to temp. Unlike computer I have found the stick to be perfectly consistent....lol

Drive the car hot and leave the car parked overnight and check the stick before firing the engine in the morning. This is the proper way to get a consistent and accurate reading, period.

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This is really important. Just because the car looks level doesn't mean it is. I wait the 5 seconds after a hot shutdown or restart and let the oil level check itself, and I get different readings all the time at various places... Find a good known-level spot and park your car there after a good hot day of driving and check the oil the next day when cold. This is your baseline.

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I hope this isn't a sign of something much worse...

I have the opposite problem: the oil level doesn't go down. A 2002, so its the 3.6 engine, 80K miles, have it for a little over 3 months now and put on about 2,500 miles. The oil level is still at the full marker on the dipstick, same as it initially was, and little darker than the original golden color. I guess that is good news, but thanks very much to everyone who wrote about how the sensor works, and general level oil behavior -- I have more to learn.

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x2 the guage and the dip stick always say the same for me

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It's great, as long as you aren't taking short trips.

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That isn't what I said. I normally don't wait the 45 seconds for the oil level indicator on the dash, because it's 45 seconds on my car. I do check the dipstick. I was merely using that the description of actually waiting for the indicator to display as a lead in to me seeing the low oil and prompting another check of the dipstick. It was not that low the full 4 weeks. Thanks for your editorial opinion about my behavior and actual facts about your oil consumption, since this is a technical forum and not glamour magazine after all.

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DBJoe996, thanks. I ordered an LN engineering magnetic oil plug and an oil filter tool to get ready for a change. Looks like I will be changing out the oil a little sooner than planned. I hope to maybe do it tomorrow. I plan on draining and measuring what I get, then filling and checking vs mileage. I don't mind a little oil burn, but if I'm right about how it consumed in a week I may need to invest in Exxon-Mobil. Prior to this I had a Subaru Impreza with a flat-4 boxer engine, which consumed about a quart every 5k mileage, so I'm used to this being normal. Sadly, I need to need to wrap up some work on an 86 vette (new radiator and spark plugs) that is occupying my garage. My driveway is sloped, way to much to consider jacking on it. I've seen some of the threads on the oil pressure sender unit, that's unfortunate. I mainly rely on the dipstick, because I am us not patient enough to sit for the f average o45 seconds for the computer to read it. One thing that I am wondering is if I actually have the right one. It's probably unlikely but I've heard it happening where previous owners for some reason put a different one in and then who knows what you are measuring it isn't the right length. I'll see if I can get a picture today and if members can confirm I've got the right one.

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Thanks Macster. I hope you are right that I'm wrong on the consumption. I hope to be able to change out the oil and filter tomorrow, then begin the monitoring regimen.

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That is what you said, owned it 1,000 miles finally waited for oil level indicator. No mention of checking dip stick. Remember a lot of car owners are absolutely clueless which you kind of painted yourself out to be on the OP.

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Sounds like a good plan! Especially the magnetic drain plug. Another good thing is to change to the LN Oil Filter adapter with a normal type spin on oil filter w/no bypass. I have noticed that my oil level guage starts measuring as soon as I turn the ignition to ON, before starting. It reads in about 10 seconds. However, if you do the same thing just after filling up with gas, it says it will take like 20-40 minutes on the countdown clock. I never wait for that one, just fire and move on. Strange behavior indeed. I know it will take some time to check the oil consumption versus mileage. Interested in hearing what you find out.

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I've been looking at the LN spin on filter adapter. I saw if for ~$150 on their site last week. Given what I've read about the bypass valve on the OEM filter and canister setup, I'm inclined to go that way. Maybe not this first change, but definitely soon. I prefer to change one thing at a time when troubleshooting or in this case nothing until I'm baselined. Interesting your oil level gauge is that quick at start up. As I plan to compare it to the dipstick now we will see. I hope the mileage vs consumption does take a while, since that would mean I was mistaken on how much was consumed in one week. If I see multiple quarts disappearing in a week, ugh. On the plus side, a 5 quart bottle of Mobil 1 0W-40 at Walmart (near me anyway) is running $23. At least I think that is a plus.

Confused on your 45 seconds to measure oil level.. Mine does it in 5 seconds? My routine is to get into the car, switch on ignition, then close door and put safety belt. By then it has read the oil level and I start. I have a C2 Mk.1. The oil level measurement seems consistent and also is confirmed if I use the dipstick.

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The only time my Boxster oil measurement count down timer reads that it will take on the order of 20 to 40 minutes for a reading is when I start the engine cold then drive just a short distance then turn off the engine as I sometimes -- but not often -- do when I leave the house for work but realize I need to stop at the convenience store just a couple of blocks from my house. When after just a minute or two in the store and I return to the car I seldom bother to even note how long the oil level check will take because I know it would take minutes and the occasional time I bother to note the time sure enough it is minutes, sometimes over 50 minutes if the ambient temperature is pretty low. Now what I think is strange is occasionally when I get back in the car and turn on the key and just out of habit glance at the count down timer just before starting the engine the count time timer is at 5 seconds. Because I know the engine didn't get up to temperature in the 2+ block drive from my house to the store I don't bother to wait even 5 seconds for the reading as I know it will not reflect reality. There apppears to be a "bug" in the DME oil level timer management code. But at all other times after the car has sat for hours overnight or for just a few minutes after being parked with the engine shut off after being fully up to temperature -- by this I mean the coolant temperature gage needle has been at the "180" hash mark for minutes -- the count time timer reads just 5 seconds and if I chose to wait the 5 seconds -- and often I do as by habit I turn on the key then while the timer counts down fasten my seal belt -- the reading is as I expect. That is because I check the oil level frequently and over the miles I see the oil level gradually fall as the engine consumes a bit of oil. The only time I see a radical change in the level is if I bother to check the oil level with the car not very level. I don't do this often, the opportunity doens't present itself often, but I do it just to note how being out of level can and does affect the reading. While the Boxster has a dipstick I never use it. I abhor the dipstick and when I had my Golf TDi -- bought shortly after I bought my Boxster -- I found having to use the dipstick to check the oil level a real chore. Same with my GTO which came after the VW Golf was sold. The Boxster's electronic oil level measurement system totally spoiled me and has put me off using a dipstick even again.

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Same here. But I have the same car, mk1. I have seen a 45-second timer before, but I don't really want to wait for that one. I think that timer is after an engine re-start while hot. If it's an engine re-start while cold, the timer countdown can be really high, many minutes long - I think I've seen as high as 59 minutes. I trust none of these except for the one that the manual indicates is proper: 5-second cold start after sitting a long time, and the hot refuel re-start. Im glad our cars have dipsticks

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It's so strange different cars have different times on this check. Mine takes 5 - 6 seconds, but after fueling it's a 5 minute countdown, I believe. 1999 model.

Using a more expensive 5w40 like Motul or DT40 reduced oil consumption in my 996

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UPDATE 6-18-2017 1) I added 1.5 quarts of Mobil 1 0W-40. This morning at a cold start, later fully warmed up after filling up with gas, and 6 hours after last driving it the dipstick and electronic meter both read full. Car continues to drive well and sounds good as far as I can tell. 2) I did a cursory check on the AOS by removing the oil fill cap. I don't yet have any type of manometer. With the engine fully warmed up and at idle, the cap came off without much effort. There was definitely a vacuum. Covering it with my hand it not did not alter the idle at all. With the engine sitting for 6 hours and then starting it and repeating this test there was about the same vacuum (simply qualitatively determined by how much I felt pulling on my hand, so not quantitatively) but with my hand off the filler tube so it was open the idle got rough. Not to the point it stalled but definitely changed. The coolant tank is roughly just under full, as it has been since the indy shop topped it off 3 weeks ago during an inspection. Still the only smoke I see is when starting a cold engine after it was last run and shut down cold (as in I ran it to move it around the driveway). There is no noticeable smoke during driving or starting the engine while warm or if it was last shut down warm after a drive. In parallel to tracking my oil consumption I'm going to build/buy a manometer to quantify the vacuum. Since the AOS seems to fail at a high rate and is somewhat time consuming to replace it seems helpful to measure this. Is any change in idle indicative of an AOS failure? Next steps this week: a) Will continue to monitor gas mileage, oil consumption vs mileage, coolant level, and amount of soot on tailpipes (I wiped these clean to provide a baseline) over the next 2-3 weeks. b) I expect to be able to change both the oil and filter later this week. At this point I'll also install the the magnetic oil plug I ordered. c) Build/buy a manometer and quantify the vacuum pressure.

if you mean idle change when you remove the oil fill cap...I believe that to be normal. I bought an @ $35 digital manometer on Flea-bay which worked fine. Just make sure it is set to the right scale!

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The idle behavior you report is normal. Removing the cap with the engine idling introduces a big intake air leak and the engine goes lean. The engine initially reacts with a drop in RPMs and some rough idling but very quickly the DME compensates. While the idle many not be as smooth as it was with the cap in place it will be better than it was right after the cap was removed. When you replace the cap this of course removes the air intake leak and the engine is now running too rich. This is not that bad of a problem so the engine doesn't react quite vigorously to the overly rich condition but it does react. But again the DME adjusts the fueling and in nearly no time the engine should have its normally smooth idle back. I can tell you after going through 3 AOS failures with my Boxster each failure was different. The first was accompanied by initial a bit of hesitation off icle and a varying idle speed. Nothing gruesome just the normal stable idle was instead "hunting". At some point -- towards the end of my attempt to diagonse the problem -- I found the oil filler tube cap impossible to remove while the engine was idling. The very last stage as I was positioning the car to get it on the flat bed tow truck was the exhaust started billowing oil smoke. The 2nd failure started out during a long 2K mile road trip. At the end of a day's drive -- 12 hours or more -- while making my way on surface streets to my hotel or sitting at the freeway off ramp waiting for the light to change -- the CEL would come on concurrently with the engine manifesting just the slightest stumble. For hours prior to this the engine just purred. The error codes suggest a mixture problem and I suspected the MAF and decided I could press on. After 2 days of driving I made it to my final destination and parked the car. The next AM upon cold start the oil smoke just billowed from the exhaust and I knew then what the CEL and error codes were trying to tell me. The 3rd failure there were no symptoms. The car was running just fine. Took off from a stop light and by habit checked the rear view mirror and spottted a large cloud of something behind the car. Suspecting a failure in the cooling system I checked for any signs of trouble at the dash but all was ok. As I drove the smoking stopped but by this time I suspected it was an AOS. I made a u-turn with the idea of driving the 10 miles to the dealer but after just a mile or so the engine started smoking again and started running poorly so I parked the car and called AAA to tow the car. Which AOS failure will you experience? Can't say. And there may be other variations too. After all my Boxster is only on its 3rd replacement AOS.

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Macster, so the idle will normally roughen up but it should come back to more or less smooth some time after I remove the oil fill cap. that is good to know. Wow, exciting times with the AOS for you. So basically it can range from a slow incremental death of the AOS to an immediate sudden failure. They say variety is the spice of life though I'd prefer this to be vanilla. The replacement isn't too bad from what I've read here and on renntech, just a long tedious job especially if you don't drop the engine (which I will not be able to do at home). We'll see what the pressure reads once i get a manometer and keep an eye on it. If I have to replace it looks like i have some long nights after work ahead of me.

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Update 6-27-2017: Coolant appears to be holding level. Based on the dipstick and measuring it cold on a flat surface in the AM before starting the engine, it appears the car has consumed about 1.5 qts of oil in 200 miles. This is on pace to equal what I previously thought was 4+ qts missing. The soot has re-appeared on the driver side tailpipe. I'm going to call this excessive since I do and intend to drive this more or less daily (the last 2 weeks had some off days). My commute is a mix of stop/go surface traffic, winding back roads, and interstate highway. I try to exercise the car as that is why I bought it. I finally got my homemade manometer built last night and will test the vacuum at the oil fill tube tonight to assess my AOS. Then we'll see what the next steps might be. Car still drives well and sounds good. Just the occasional white cloud at start up consistent with shut down of a cold motor.

That is some excessive consumption. The AOS breather connection is on Bank 2, right side of engine, which is the drivers side (left) tailpipe. Sounds like you are on the right track.

Can you open the coolant cap and check if the coolant is clear? Does the car make any tapping noise at idle after fully warmed up? It sounds like a mechanical problem (rings, bore scoring) in bank 2.

^^ I didn't want to go there yet but that's what I was also thinking. Next up should be compression/leak down tests on Bank 2, and maybe boroscope while in there. You can also drop the oil sump plate and inspect the cylinder bores that way. While the spark plugs are out inspect those as well. A lot can be determined by how the spark plugs look.

I'd pull an oil sample & get analysis. You can have at least a portion of the cylinder walls checked with the plugs out for a few hundred bucks of labor. A compression test may show a red flag. Overall though, the more data points you get the better informed you'll be. Good luck going forward.

Call in the fat lady, she's singing on this one.

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Yep. This morning I opened and used a pipette to remove some since I can't see worth crap inside that tank in the engine bay. I did this to verify what color coolant I had (no idea when it was changed last and I wanted to be ready with coolant should I need it). The color that I sucked out was light orange/pink, with no emulsification or particles in it. So I think it qualifies as clear. Prior to withdrawing the sample I used the pipette to "stir" the tank to see if there was sediment or localized concentrations so I could get a good sample. Not a end-all-be-all conclusive test but best I could do this morning to assess. I will repeat again though a few time over the next several days.

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meaning you think it's AOS or a mechanical issue in the engine itself?

He thinks your engine needs to be rebuilt on some level. Based on the consumption level & tailpipe soot, it could be a good idea for you to try and get a different data point or two that will reinforce or disprove the theory that your car has some scoring issue that's caused a cylinder to consume oil at a rate far above what regular specs allow. My suggestions are an attempt to try and verify the scoring theory. A borescope could help and high deposits of cylinder lining material in your used oil sample would corroborate this & give you enough confidence in the diagnosis to pull the trigger on some type of remediation. It may be a case where you can continue to drive the car, but doing so puts the engine case at risk of a more serious failure downstream. If I were you I'd get in touch with a good indy and/or start investigating re-sleeving options for the cylinders.

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At the rate of consumption either the AOS is shot but in that case you would have massive amounts of smoke at startup. So my money is on a scored cylinder or multiple cylinders with a decent amount of blow by causing you to consume oil at a rapid rate. I think she's got to come apart and have a rebuild to one degree or another.

bring it to a shop where they will remove the sump plate and inspect the cylinder walls from the bottom of the engine. that's the only thing I'd be doing at this point.

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Update 6-28-2017: With engine cold, just started I measured a crank cave vacuum using a water manometer at the oil fill tube of 4-5 inches water. The engine was having some trouble adjusting to me taking the cap on and off multiple times as I set up for the measurement, hence the range in measurement. After a 20 mile drive and the engine temp at my normal of the right hand edge of the "8", and after many curious looks in the Wawa parking lot I measured 4" of water vacuum. Based on my limited knowledge, this does not indicate an AOS problem at this moment (realizing it might change). This values are in teh "normal" range. Dissappointing. I'm probably the only person on this forum hoping for AOS failure. Well not really. There is a mechanical tapping sound. I took video of it with the engine idling cold just after start up and hot after the 20 mile drive. I am in the process of trying to convert it to a supported file format. It may have to wait until I get home from work though. I do need to add that when I first got the car I had it checked out by a local indy shop, and they found what they thought was a sticking lifter (not sure which one), and they added an additive to the oil to boost it. I believe the sound they heard and what I hear are one and the same. If you close your eyes and imagine, the sound is a steady tick-tick-tick-tick.

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unfortunately my thoughts are scored cylinders. get it scoped.

Sorry to hear that. The AOS reading even at 8" of water would not cause such high oil consumption and your mechanic was likely wrong. Your symptoms scream bore scoring like AWDGuy said.

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As I put in motion to see a different local indy shop on this, is there a definitive discussion on the bore scoring issue on rennlist or renntech? My searches so far are coming up with mentions of it in the context of troubleshooting (like this thread) but not a comprehensive discussion as there is in several places on something like the IMS bearings (root cause, design defects, manifestations of the issues, consequences, remedies, false gods to pray to, etc). Would like to learn more in parallel to whatever a tech may tell me. Thanks.

Water temp was near the 8 of 180 F and the vacuum was measured at 4. So AOS looks good.

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lots of threads discussing this and the causes. not everyone agrees on route cause. some will say it's the material in the block allowing the cylinders to taper and eventually oval to the point that scoring starts. some say it's because these cars are driven in the cold. Porsche says it's crappy maintenance. a car costing 100k + shouldn't experience scored cylinders at 60k mile mark. that's *my* opinion of course and why I would never buy a porsche again - even new 9A1 and Cayennes suffer from this manufacturer fault. it's ridiculous. find a shop that will remove the sump plate and scope from there. it isn't a hard job to do at all....shouldn't be more than 1 hour labor.

...and I'm sorry man re-reading this thread brings up a lot of memories how my 996 purchase went down. so many lessons learned.

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So out of curiosity, where do scored cylinders ultimately lead to? I imagine: - you lose compression and the combustion process takes a hit causing multiple issues (loss of power, emissions issues, NVH) - maybe the scoring over time spits out more particles and those start to find there way into other moving parts in the engine causing premature failure - obviously burning more oil - local overheating in the cylinders causing other issues? - what else? I guess I'm looking to understand how this might ultimately lead to my engine euthanizing itself. Does the engine basically start to eat itself alive? Not saying I'm going to take risks, especially since the root cause of my issue is still not confirmed. Just learning. Thanks Disregard - I'm starting to piece it together https://rennlist.com/forums/996-foru...cylinders.html

sorry you won the reverse 996 lottery

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a few here just add oil and keep driving it. I know for a fact there's a c4s going around ottawa now that has severe scoring in all cylinders on bank 2 and all he does is add oil. I could have kept driving mine....just had to keep adding oil every gas fill. there was very little performance lost as i was still tracking it and pulling on cars that had some pretty good HP. but yeah, the engine is basically eating away at itself at this point. I felt it was only a matter of time before something really bad happened and I was better to fix the core I had than to source another when things went horribly wrong. out of the failures to have, this one (scored cylinders) is the one you want. most other modes of failure take out your block which adds to the rebuild costs significantly.

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I need to pass emissions inspection here in MD in the next 30 days, so that may dictate what I do or don't do and how soon. I'll get it checked in the meantime, ideally tomorrow just for the sanity of definitively knowing whats going on. I saw what Flat6 Innovations was saying in the linked post, and understand the extreme end. I also saw people posting experiences like you describe: drive it, feed it oil, monitor it, and plan for the work someday.

I'm not sure what is included in your emissions testing but we had the sniffer test here in Ontario at the time and I passed with flying colors. here is a pic of my scored cylinders. 20150309_223405_zpsu8kyrood.jpg I tracked and emission tested the car like that. https://youtu.be/U65YkjOObRo here I am tracking it with scored cylinders. she burnt less oil on the track than regular driving!

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I was told by a mechanic that these cylinders have sleeves in them? About how much for a scored cylinder job?

doing it yourself cost me about $18k CDN. Everything inside the motor that could be replaced, was.

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Finally got the videos converted. The one with the engine bay is with the car cold, just started right after I did the AOS manometer test. The one of the underside is after it's been fully warmed up.

can't play them from my phone. can you upload to youtube. ?

this is mine with cyl 4 & 6 toast https://youtu.be/YSRTKH89MdM

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Good idea. Didn't think of that. Much simpler than trying to sort out different file types and codecs for various device platforms. Engine cold You Tube Engine at temp You Tube

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Was that actual liquid oil spit out your tailpipe onto that rolling tool box?

yes. My cylinders were scored to hell.

just listened to them (your vids) you have scored cylinders.

Sorry, man. I have to agree with AWDguy ​​​​

Bore score, motor is done. Either drive it and feed it oil until is grenades or shut it down and start the repair process.

Update : I got visually confirmation of the scoring on the passenger side bank on what I think is the middle cylinder. I had some small metal shaving in the filter too. I used a desalt horoscope which as a little too bulky to look everywhere it it provided evidence of at least one cylinder scord. Just wantd to get back and close the loop that the evidence supports the forum diagnosis. In a separate thread I’m looking for shops that can perform the repairs. I don’t want performance upgrades, just want this fixed as a I love the car. Everything is going Lise is great with the car. The costs I’ve seen posted are terrifying so not sure what I’ll ultimately end up doing. I’m naively going with that my core is ok. This is way beyond my skills and tools to repair myself, so that is not an option. For those on this thread that have been done this road I’d like to hear the steps/process and your experiences with it. I recently got a CEL with code P0011, which one of the causes I found in research was continuous oil flow into the vat/vat piston chamber. I’ll be rechecking th Aos now too.