Discrepancy between dip and electronic oil level measurement

Till recently I got quite consistent readings for the oil level between dipstick and electronical gauge. Especially at the higher levels both dip and electronic were almost spot on the same. At the lower side the dipstick indicated slightly lower levels, but still comparably close. Some 2 weeks ago I got an X51 type oil pan installed (ordered via Brombacher) together with a switch to Motul 300V 5W40 (Xcess 8100 5w40 before). Car also got a new suspension. Which dropped the car a lttle bit. Front 4-5mm extra then back. Since then the consistency between both oil level readings is not anymore what it used to be. For example today I pulled over at a gas station and waited 5 minutes. Car was level. The engine was hot. The electronic reading was 1 bar below max. the dipstick showed almost at min level (lets say around 1/4 between min and max). Are both measuring systems located at a different place in the sump? Could the X51 pan influence one or both measuring methods?

I would say from a logical perspective that the deeper oil pan will not change the max/min level of the oil, it only increases the volume of oil. I have always found no discrepancy between the electronic reading and the dipstick level, however, I have heard of such. Since the engine was hot, perhaps the circulating oil had not had a chance to drain back to the pan so the dipstick was showing low. The electronic reading is not 100% accurate, I take more like "there is some oil in there or it is low." I always depend on the dipstick and only after the car has been run and then has sat for at least 30 minutes.

I don't trust my digital reading at all. It seems to vary where as the dipstick stays very consistent.

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Were you careful to remove the dipstick and wipe it dry then insert it *fully* and remove it and then check the level? The two systems are not in the same place. Ideally the best place is in the center so any out of levelness will have the least amount of effect on the reading. But both the dipstick and electronic sensor can't be located in the same place and the other engine items both outside and inside the engine also have to be taken into account. So both may be located sub-optimally and this not only can account for different readings but possibly wildly different readings too between the two systems. I don't bother using the dipstick that is in the Boxster but with the electronic oil level system the oil level readings are different if the car is not level. With the car parked straight on a very slight up slope the level is down maybe a bar. The same amount of tilt to either side though has a greater effect. I seldom park with car on a down slope and I don't like to back in a parking space just to take a reading with the car oriented 180 degrees opposite to see how this effects the oil level reading. The Boxster has no restriction on the car's degree of level. I could probably check the oil with the car upside down. But in the case of the Turbo it is pretty sensitive to how far out of level the car is. This suggest to me the oil level sensor is not optimally located and Porsche seeks to limit the upset varying level readings could have by limiting the reading to only occur if the car is level enough. Since there is a level sensor anyhow to support PSM this is a almost for "free".

Yes. I understand that the absolute oil level is not affected by the deeper oil pan. Therefore the dipstick should be measuring the same levels as before. Was not sure if the electronic measurement could be confused. As I said, before readings were both pretty accurate. I will follow the prescribed procedure to measure with hot engine after waiting 5-10min, i.e. after refueling.

No matter what the owner's manual says... No matter what anyone says, I NEVER trust the electronic reading until "stone cold 24".... Meaning engine is stone cold and has sat for at least 24 hours on a level surface without being ran at all. I fight this constantly with customers and their oil levels, and have learned that the oil takes too long to return to the sump for the gauge to be accurate as described in the owner's manual. Look for The Knowledge Gruppe to publish a directive about this in the near future. People are over filling engines and causing oil consumption issues over and over again.

It's not rocket science and it's very simple. There are two factors that affect the oil level. 1) Whether most of the engine oil has drained back to the sump 2) The temperature of the oil. Oil expands when hot. From 70F to 220F, the level will rise close to 1/2 quart (since we have ~9 quarts)! Between the 'min" and "max" marks is only about 1.25 quart on the dipstick. From the above 2, you can logically conclude that the only consistent way is after a drive (engine fully warmed up), leave the car parked overnight to let most of the oil drain back to the sump. Then check the oil level in the morning. (ambient temperature differ for tens of degrees at most so oil expansion/contraction is negligible).

I conducted a 3 month study on this over the winter. As soon as June rolls around I'll do another 3 month study in hot weather. The expansion of some oils, especially Driven DT40' and Motul 8100 can skew the readings even more. Also, oils like DT40 are very clingy and still to the upper end components longer. People are adding oil to the genes that appear to be low, and then over filling them. It's happening every day, this is why the 9a1 engines check the oil while the engine is running, much like an Aircooled Porsche. I also tell my customers to keep the oil level in the middle of the gauge when cold... We avoid filling to the top line of the indicator.

Oops our posts crossed...my previous post was directed to the OP. It's interesting to know different oil expands at different degrees so that's another reason for checking the level only at ambient temp (assume you don't live in the North pole).

What are the immediate symptoms of an over filled engine in our 996's?

Thx for the insights. With standard procedure I also referred to dipstickwise. I will keep a close look for the coming weeks what the dipstick tells me about the oil level when either hot or at ambient temperature sitting overnight. It would sound logical that you want to have enough oil when running hot. As more oil will be splashing/ spraying around somewhere higher in the engine, I mean it will not return immediately back into the sump so more oil will be somewhere circulating while in operation.

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A cold engine will almost certainly have more oil in suspension than a hot engine all other things being equal. The cold oil will be slower to drain from the internal engine surfaces and slower to react to the scavenge pumps so it can be returned to the sump. Still a hard working hot engine can keep a quart possibly more in suspension at high RPM. Quite a bit of the oil is in vapor form. I'm careful to avoid overfilling my engines with oil so when I check the oil level cold -- with my Boxster, the Turbo can only be checked with the engine hot (and idling and on fairly level ground) -- and find it down a bar or two I do not top the level up as I know once the engine/oil is hot the level will be higher. I see this when I stop to fill up the gas tank -- after often driving hundreds of miles non-stop so the engine is fully up to tempeature -- and as is my habit check the oil level after filling the gas tank. The level is up. For the Turbo I check the level and it can only be done with engine up to temperature and in this case if I see the level down a few bars I add enough oil to bring it up to the max line. I prefer to with my cars run the oil level -- hot oil level -- at close to but not over the max line to ensure both engines have as much oil as the factory intended so there is little risk of the engine pulling in aerated oil. My concern is with a low oil level and under hard cornering and on mountain roads that can have a pretty steep grade too boot oil can move to one side of the oil sump and as the oil level drops on one side the still aerated oil can flow into the where the oil pump pick up is located and the engine can be fed with this aerated oil. I have come across reports of other engines while being dyno'd having a sudden fall off in power at near red line and this was traced to the lifters receiving aerated oil (due to an adequate oiling system) and this oil compromises the lifters abilty to operate correctly. One has to wonder how this aerated oil affects the main/rod bearings but I guess that the engine didn't spin a bearing or worse suggests the bearings are a bit more tolerate of this aerated oil.

my bet is with-in 10 years ALL manufactures will completely seal the engine/drive train from owner access. i like to think of it as tinkerbell proofing. checking the oil is just beyond some

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In 10yrs it will be electric! So no more engine oil to check...

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Well before that we'll have "lube packs" that fit into the bottom of the engine oil sump. These will hold a full load of oil for a XXXX mile service, as well as the oil filter. To change the oil and filter you zip off a quick disconnect plate, and remove the lube pack, then discard it, and replace it. I have already been part of some developments based around this. The 9a2 engine is getting close, plastic sump plate, and 1/4 turn drain plug is a reality with those 2017 models. We ordered a plastic sump plate, and within 2 days had a billet aluminum replacement with a real, magnetic drain plug. The OE unit we received was made less than 3 weeks before we received it, and we'd already improved it. I hate plastic junk.

The electronic oil level gauge uses extrapolated data from different sources to estimate the oil level. Driving at high rpm's before turning off the engine leaves more oil in the heads that can't be measured accurately by any means. It's far better to drive the car a quart low than 1/4 quart overfilled.

it goes further than oil in the heads.. The heat exchanger alone can hold 1/2 qt of oil, and you can have another 1/2 qt held in other crevices of the engine. The AOS lower lend also holds some oil, especially on post mid 2002 engines with the later style AOS. This is why you learn to never even look at the freakin gauge, or even the dipstick, unless the car has sat "stone cold 24". I preach this with every engine we deliver. If you take time to measure the oil at different temperatures and durations of time after shut down, using a graduated cylinder, or the like will reveal a ton of information. Also, some oil will measure differently than others, and yes, aeration of the oil also impacts the "virtual oil level". Check the oil "stone cold 24" and keep it between the top, and bottom lines, and you simply will not go wrong. Be **** about it, check it every damn time you shut the car off, and try to keep it on the top line, and you'll pay for those choices with increased oil consumption, shorter lived AOS units, and even false fuel trim deviations. I have ran an M96 engine 6 quarts low on purpose, and didn't hurt a thing... On the track it would have, but it you are 1, or even 2 quarts low- no big freakin deal.

after contacting the national weather bureau ,blackstone labs,saybolt seconds universal chart,laser level car [us spec] i have concluded my oil level is okay ......for the northern hemisphere only. i kinda feel sorry [not really i am lmao] for the person here that checks his oil TWICE a day another thread i must share with other mere mortals

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Yessir ... I will follow your advice. Thanks a lot for the input.

After some more testing and comparing I can now confirm the electronic measured oil level is still consistent with the dip stick. So the previous discrepancies I got were probably related to not so perfect measuring conditions which I overlooked. Overall on the mental side quite happy with the deeper sump and the extra oil it holds

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I'm glad you started the thread. I didn't know the effect conditions had either. I just assumed the electronic reading was inaccurate. Good stuff.

I've only had my '01 C2 thru one oil change. In the early days of ownership, I'd check the electronic dip stick fairly regularly. After 2000 miles or so, I felt confident I wasn't burning any oil, so I stopped checking. Then, just this week, I happened to stop to fill up. I never really paid attention to the post-fill-up oil reading indication, but this time I looked at it and was quite low. Like one bar above the min mark. Hmmm.....never saw it that low. So after the conclusion of my drive, I checked the physical dip stick, and it was full. The next AM, I purposely let the oil level countdown indication run its course. One bar below FULL, which is where it's always been. Just reinforcing that a) trust the physical stick, and b) ensure consistent conditions when checking the electronic.

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That "stone cold 24" won't work for me as my Boxster seldom sits 24 hours unused. As long as the engine was up to temp when I shut the engine off the night before the next AM when I go to check the oil I have a high degree of confidence in the reading. And when after the engine has been run enough to be considered fully up to temperature and I shut off the engine the next time I go to start the engine if the oil level count down timer starts at '5' I have a high degree of confidence in the reading. As long as the engine and oil is still fairly hot, the reading will be higher then when it was cold but this is to be expected. I don't add oil on a "low" cold reading only on a "low" hot reading. I know the electronic oil level system comes in for some dislikes but I much prefer it over the dipstick. When I owned cars with a dipstick it felt like a trip back in time to the '50's err make that the '80's (don't want to show my age) when at say the gas station I'd raise the hood and go through the steps to check the oil level with the dipstick. Like using a dial phone. Or getting up to change the TV channel or adjust the volume using ***** on the TV set. And the Turbo doesn't have a dipstick. Even though the oil can't be checked cold I even like this system. With the Turbo oil level sensor/system as long as the engine is up to temperature and the car reasonably level I can check the oil any time, even at a stop light.

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I like that - always trust your stick. Good rule to live by.

Do as you wish. I know what works for me, and those who trust me to fill their engine compartment. I also know what does;t work, and what causes problems. As far as no dipstick on a Turbo, any 996TT I build will have the dipstick conversion made. When I do my "major" service on a TT I also add the conversion. I trust what my eyes can see more than any electronic gizmo. Installing water jackets and pistons today in this 996TT.

I think this is the point in the thread where Martin will call Jake out for something that doesn't actually appear in the photo in post #25.