Driving 2008 CTT for 5 years now. Some time ago got an engine rebuilt. Engine used around 1L per 1000km in a mixed mode. Just before the rebuild it would use 1L per 300-400km, had scores and slapping sounds. Got new cast iron cylinders. After rebuilt I would not add any oil during first 2000km. Then was an oil change. The next 3000km it would use around 200-250ml per 1000km.

But all these 5 years I had a weird behavior of Oil Sensor. It would throw "Check Oil Level" message while the oil level if FAR ABOVE the Min mark.

Here is the image example I had recently:



When I stopped after first time the message appear, I tried to choose a flat surface. It was a cafe near the highway. I can't say it is perfectly flat surface. But I don't get how the level can differ around 250-300ml after driving 90km and measuring at parking (which has concrete floors and IS flat). I assume either still a surface curve, or moisture vaporized. However I still drive in easy mode - 90-100km/hour max, no hard accelerations, etc - to let the engine properly break in before at least 6000-7000km.

I have strict rules:
- I check oil and anti-freeze levels every 500km or every 1 month (depending on what comes first).
- Oil temperature is at the working level (I drive min 15-30 minutes).
- I stop and let the oil get back into the pan for 15 minutes.

Now there are 2 things that annoy me:
1. Why the oil sensor pops "Check" message while the level is far above? Does anyone know the logic behind it? Is this behavior considered wrong and should I replace it?
2. The oil consumption is 200-250ml per 1000km. I have used 600ml per 3000km/ However in the first 1500km I didn't fill it, there were no "Check oil" messages and the level barely change. Now it SEEMS to ask more, without anything else chaning (drive mode, style, etc.). There seem to be no leaks, the engine sounds just perfectly fine. I assume the consumption will rise after some time, but not now. I was also told by a guy who works exclusively with Cayennes/Panameras that a normal consumption (even for turbo-charged systems) should be around 2L per 10000km (200ml per 1000km), and in hard mode - up to 1L per 1000km.

 

I believe your consumption amount is fine. The reading difference can be from accumulated moisture evaporating away once the engine is run at a higher operating temperature. If the original reading was done cold and then the subsequent reading done at the cafe, a bunch of oil is pumped up into the motor and even waiting 15 minutes won't allow it all to return to the sump. The error message you're getting sounds like you have a faulty oil level sensor, and it should be replaced. The dipstick level you're maintaining (around the A when hot) is perfect) as that allows for a little thermal expansion of the oil.

 

Thank you for the reply.

I am curious, how "strong" the moisture factor affects the level difference. Sometimes I am really surprised with the dipstick measurings. Keeping the same steps, same place (flat underground parking) and most of the time the readings are predictable. But sometimes the oil is just "gone" 200ml without understandable reason (same season so no temperature jumps, same chill driving style).

And sometimes the level gets even up (moisture? more oil got returned into the sump?).

Also I now never do cold readings. So every time, I would run the engine for at least some 15-30 minutes going some place, then wait 15 minutes at parking. Then measure.

The check oil warnings are really annoying. Especially when one has to drive some longer distances. I want to think the car is reliable and want make problems in the middle of the road.

 

Honestly, once the engine has been run, the levels can fluctuate a bit based on engine temperature, outside temperature, and how long the car has sat from when it was shut off until it was restarted. If you really want consistency in your measurements, check it cold on level ground at the start of the day before the engine has been run and just make sure the lever is at the bottom of the "X" in "MAX" as even hot, you won't get more expansion than that where it will still be below the top line on the dipstick. That's what I do with mine. A number of short trips in a row or cold outside temperatures that keep the engine temp lower can build up quite a bid of water condensation in the oil. When there's a lot of water, that's when you see the milky yellow foam on the underside of the oil fill cap. That's nothing to worry about as long as you do a long drive that fully warms up the engine and evaporates the water away.