Minimum Oil Level Reached
#17
Just seeing the level isn't the full story and for something as critical as your oil, blindly trusting sensors without being able to verify (short on a full oil change) just seems foolish. Its not even like we are talking about something that takes significant space, engine power, or cost to exist. The sensors are good for those that never open their hood, but chances are that by the time they alert some level of damage has been done (in terms of reducing the longevity of the motor).
As sensors go, I don't like this one anyway as you have to actively check it. In the 996 it shows me the oil level every time it starts with on action on my part. I still check it from time to time, but I'd know if it was starting to drop for some reason before it got to the "needs oil now" point.
#18
Well, I'm old school. Once you get to know a specific car, it's possible to correlate oil pressure with oil level. My old Benz turbo diesel ran consistent above 3 bar. As soon as I saw the gauge drop below three, I knew it was time to add a quart. Dipstick agreed every time. Since oil pressure is avaIlable to the Cayenne driver in at least two locations, it represents a reasonable check on the electronic dipstick
#19
I'd like to look at it now and see if it moved from the mid level mark in the 2 days but I can't without starting the engine and bringing to operating temperature. The other method mentioned of looking at oil pressure, well for the same reason that's not a possibility. The benefit of the simple old metal measuring stick is obvious now.
#20
The tech is saying don't start the engine again because it has damaged the bearings now, it is that simple. The more you run it further damage will be occur. It wont get better by bringing the engine up to operating temperature that is for sure. Running the engine will now only increase damage and/or chance of catastrophic failure because as the oil heats it thins and any excessive clearances open further... and, more damage occurs from the already damaged running surfaces further contacting one another. They obviously want the chance to recover the engine if that is still possible. The less damage the less expense. They may be able to rebuild it cost effectively, they may not, but they would like the opportunity of making that decision. Running the engine to destruction may also void any chance of warranty because it is the operators responsibility to shut the engine down if it exhibit obvious signs of a problem....which it has some time back when the ticking first started. This is really when the problem should have been reported, not now.
The engine has been consuming oil since new as many of these engines reportedly do and it really is up to the operator/user to regularly check the level particularly in the running in stage when oil consumption is expected. That is why there is a gauge or a dipstick....oil temp gauges etc. The consumption did not occur due the ticking/knocking noise. The ticking/knocking noise is there purely because of engine damage from insufficient lubrication.
The oil consumption has reduced the level of the oil beyond a point where the viscosity can recover due to the operating conditions the engine was being subjected to. Once the oil level becomes low viscosity is unable to recover quickly enough hence why engine damage occurs. When there is the correct amount of oil, viscosity recovers very quickly even though the oil can get very hot as it passes through the engine. The higher the engine loads the higher the oil temp becomes. Once the oil returns back into the sump (or reservoir) the viscosity recovers (oil cools) as it meets with oil that is awaiting to pass through the engine.
When there is an insufficient oil level the oil that passes through the engine has absolutely no chance to recover and becomes immediately picked straight back up again by the pick-up and pressure fed back through the engine again. After repeated cycles the oil cannot protect the running surfaces as it has lost its lubrication properties. The consequences are inevitable. That is why it is not recommended to operate the engine under any form of load when the oil level is low. Best to drive very gently and fill to correct level.
The engine has been consuming oil since new as many of these engines reportedly do and it really is up to the operator/user to regularly check the level particularly in the running in stage when oil consumption is expected. That is why there is a gauge or a dipstick....oil temp gauges etc. The consumption did not occur due the ticking/knocking noise. The ticking/knocking noise is there purely because of engine damage from insufficient lubrication.
The oil consumption has reduced the level of the oil beyond a point where the viscosity can recover due to the operating conditions the engine was being subjected to. Once the oil level becomes low viscosity is unable to recover quickly enough hence why engine damage occurs. When there is the correct amount of oil, viscosity recovers very quickly even though the oil can get very hot as it passes through the engine. The higher the engine loads the higher the oil temp becomes. Once the oil returns back into the sump (or reservoir) the viscosity recovers (oil cools) as it meets with oil that is awaiting to pass through the engine.
When there is an insufficient oil level the oil that passes through the engine has absolutely no chance to recover and becomes immediately picked straight back up again by the pick-up and pressure fed back through the engine again. After repeated cycles the oil cannot protect the running surfaces as it has lost its lubrication properties. The consequences are inevitable. That is why it is not recommended to operate the engine under any form of load when the oil level is low. Best to drive very gently and fill to correct level.
Last edited by speed21; 04-08-2013 at 03:53 PM.
#21
Bearings could be damaged as you seem to be convinced but I suspect the problem as a scored cylinder or something else like tappets up high on the engine. I'm hopeful to find out what the issue is/was if/when the dealer figures it out. I think they will be picking up on Wednesday morning. When the MOLR showed, I put a quart of Mobile1 in when I arrived at home maybe 5 miles later. If that's not good enough then the warning level guage was improperly installed or calibrated. Assuming it was installed and working correctly, the ticking/clicking did not come from insufficient lubrication as the oil level was never less than 5 miles from minimum. I'm pretty familiar with how engines work, oil lubricates, and how heat effects things. The sound it is making is almost exactly the sound you hear if you ever adjusted tappets on a car when the spacing was too open with the valve cover off. Will definitely post more information when it's known. Interested to know what others think it might be. BTW, nobody said it would get better by bringing it up to operating temperature. I was remarking that one can't even check the oil level unless one does that--hence the need for an oil stick.
Last edited by nhirsch; 04-08-2013 at 04:22 PM.
#22
Burning oil seems to be common enough that a lot of people say its normal, but a quart in 7k on a brand new engine seems ridiculous to me.
I've certainly seem minor drops between oil changes, but unless it was an old engine that I suspect was abused early in life I've never seen an engine burn enough oil that it dropped below the minimum. In fact the only time I've added oil mid cycle was in my Jag when they changed the fill amount and sent me a new dipstick.
I've certainly seem minor drops between oil changes, but unless it was an old engine that I suspect was abused early in life I've never seen an engine burn enough oil that it dropped below the minimum. In fact the only time I've added oil mid cycle was in my Jag when they changed the fill amount and sent me a new dipstick.
#23
I'm not convinced as such as i'm not there on the ground, but based on your sound clip thats what it sounds like to me. The noise to me indicates a serious problem. Damage can occur very quickly when oil levels are low. If you say the noise is high up in the engine then it could well be a scuffed piston/cylinder bore....or even a stuck lifter (although then there should be a miss or choofing sound). Cylinder damage is usually followed by excessive smoke from tailpipes.
The clip did have the engine sounding rather noisy though. The piston crowns in these engine are cooled by oil squirters....may also be gallery cooled so if oil levels were low and the operating loads high then viscosity is down creating an unfavourable environment and potential for piston scuff. Best to keep oil levels at correct level.
Once there is any form of scuffing debris enters the oil system and then all sorts of damage occurs throughout the engine. If it is a lifter (bucket) then by sounds of it, it sure has a hell of a lot of excessive clearance. Doubt that can be fixed by re shimming. My money is it on being something far more sinister going by your clip....piston/bore.....B.E bearing....one of these two, or both.
All the best with it.
The clip did have the engine sounding rather noisy though. The piston crowns in these engine are cooled by oil squirters....may also be gallery cooled so if oil levels were low and the operating loads high then viscosity is down creating an unfavourable environment and potential for piston scuff. Best to keep oil levels at correct level.
Once there is any form of scuffing debris enters the oil system and then all sorts of damage occurs throughout the engine. If it is a lifter (bucket) then by sounds of it, it sure has a hell of a lot of excessive clearance. Doubt that can be fixed by re shimming. My money is it on being something far more sinister going by your clip....piston/bore.....B.E bearing....one of these two, or both.
All the best with it.
Last edited by speed21; 04-08-2013 at 04:45 PM.
#24
Burning oil seems to be common enough that a lot of people say its normal, but a quart in 7k on a brand new engine seems ridiculous to me.
I've certainly seem minor drops between oil changes, but unless it was an old engine that I suspect was abused early in life I've never seen an engine burn enough oil that it dropped below the minimum. In fact the only time I've added oil mid cycle was in my Jag when they changed the fill amount and sent me a new dipstick.
I've certainly seem minor drops between oil changes, but unless it was an old engine that I suspect was abused early in life I've never seen an engine burn enough oil that it dropped below the minimum. In fact the only time I've added oil mid cycle was in my Jag when they changed the fill amount and sent me a new dipstick.
Last edited by speed21; 04-08-2013 at 04:58 PM.
#25
If one quart brought him up to the midway point on the cluster, then he was just barely at the minimum level when the warning came up. He would have to be lower than that for oil starvation to occur unless maybe he had the engine at redline the whole way home.
Burning one quart in 7k miles is not bad for this engine. The reason Porsche updated the way the oil level reads is because of consumption complaints. By changing from a one liter scale to a two liter scale on the oil level display, it doubles the length of time before the warning comes on, so customers are less likely to see the warning before their regular oil changes.
One of my customers had a 2011 Cayenne S that would burn a quart every 1,000 miles. It was still within Porsche's "acceptable limits", but there was clearly a problem.
Burning one quart in 7k miles is not bad for this engine. The reason Porsche updated the way the oil level reads is because of consumption complaints. By changing from a one liter scale to a two liter scale on the oil level display, it doubles the length of time before the warning comes on, so customers are less likely to see the warning before their regular oil changes.
One of my customers had a 2011 Cayenne S that would burn a quart every 1,000 miles. It was still within Porsche's "acceptable limits", but there was clearly a problem.
#26
If one quart brought him up to the midway point on the cluster, then he was just barely at the minimum level when the warning came up. He would have to be lower than that for oil starvation to occur unless maybe he had the engine at redline the whole way home.
Burning one quart in 7k miles is not bad for this engine. The reason Porsche updated the way the oil level reads is because of consumption complaints. By changing from a one liter scale to a two liter scale on the oil level display, it doubles the length of time before the warning comes on, so customers are less likely to see the warning before their regular oil changes.
One of my customers had a 2011 Cayenne S that would burn a quart every 1,000 miles. It was still within Porsche's "acceptable limits", but there was clearly a problem.
Burning one quart in 7k miles is not bad for this engine. The reason Porsche updated the way the oil level reads is because of consumption complaints. By changing from a one liter scale to a two liter scale on the oil level display, it doubles the length of time before the warning comes on, so customers are less likely to see the warning before their regular oil changes.
One of my customers had a 2011 Cayenne S that would burn a quart every 1,000 miles. It was still within Porsche's "acceptable limits", but there was clearly a problem.
#27
Dealer is checking to arrange a loaner to put on the flatbed. Car is patiently (pun intended) resting in my garage, empty of personal contents, awaiting gurney to the 'operating room' tomorrow (Wednesday).
Last edited by nhirsch; 04-09-2013 at 07:38 AM.
#28
"First top up the oil level to the MAX value and then add an additional 0.5 liters of engine oil."
My personal belief is that they determined that an additional ½ liter of oil would do no damage, and would help keep the higher-consumption vehicles out of the workshop a little longer.
#29
I won't argue with a TSB (which is two model years old by the way), but my manual says I'll get a "gentle" reminder on the MFD when 1 qt is required. If I ignore the warning, I get a more stern/urgent reminder once it gets 2 qts low. But for the CD, it seems this is academic. I'm 200 miles shy of my first oil change, and the electronic gauge reflects no usage at all
But I'm going to extract my own oil, which allows me the option of metering what comes out; some of which will go to the lab to determine fuel content
//greg//
But I'm going to extract my own oil, which allows me the option of metering what comes out; some of which will go to the lab to determine fuel content
//greg//
Last edited by grohgreg; 04-09-2013 at 12:02 PM.