I've read the threads here, on other 997 forums, and contacted several dealership sevice departments and can't get a consistent answer!

My car is a 2005 997 (997.1) C2 coupe.

Last night, after driving home from the office, I checked the oil level. I shut off the motor and waited for the timer to count down (about 5 minutes) and give me the reading. It was right on the "min" line. OK. I said, I'll go buy a quart of 0w-40 and add some. But then in my infinite wisdom, I decided to wait until morning and check it again dead cold (as cold as it can be living in Austin TX and after 6 seconds it read 1 full mark above the "min" line! (each mark being about about 1/3 of a quart I think). BTW, my garage is dead level.

The manual is a bit nebulous about engine temp for checking oil level too, so I want to put it out here again and see if I can get some help!

I've been a 911 owner and wrench turner for 25 years, but this is my 1st venture into the liquid cooled...I damn sure know how to check the oil in the air cooled cars!

Thanks, and apologies if this topic has been beat to death.

 

Check pages 118-119 (or thereabouts) in the owner's manual - procedure is detailed there. I meant to include the relevant pages.

 

Yes, I've read that. It says hot or cold basically, right? But I get different readings for hot or cold after the timer finishes. So lets say if I use the hot reading in my thread (right at the "min" line) and add a quart. If I did that, the cold reading (which showed at the line just above the min line) I would end up overfilling by 1/3 of a quart right?

I would have expected the hot level to be higher because of the volume increase of the heated oil assuming all the oil made it back to the bottom of the motor. The difference between hot and cold oil made a huge difference in the air cooled cars, alway reading higher at temperature (which is the proper method in those cars...engine idling)

I'm confused :-P

 

It is confusing...though I don't think it says "hot or cold" but says at operating temperature...which is ambiguous too. It's a big crankcase so I never add in quart increments but in 0.4l increments which I believe is the equivalent of one bar. Then you can check again without worrying about overfilling. Good luck.

 

OP - I am not THE expert and have also read the threads. As I understand it, the oil level display is measuring the last (quart) of oil. In other words, if you see ANYTHING on that display at all you are in good shape. Hope that helps.

 

It takes hours before "every drop" of oil hits the bottom of the engine; thus, you read higher in the morning.

Always check it in the morning and try to hit 2/3 or full. I never trust the 1/3 mark since it could trigger the 'add oil' dash message after the oil gets distributed throughout the inside of the engine. (been there, done that)

 

yeah best to check in the morning on a cold engine before starting up because all of the oïl has seeped back down by then, plus it only takes 5 seconds. And you don't want to run a 997 on the low side in order to prevent oïl starvation, even though that's unlikely it's just safe practice to keep these integrated dry sump engines filled up.

 

The best way to do it is measure it frequently and notice the trend. You've measured it hot and cold but what it's telling you in both cases is that you should add a little oil. Put in a quarter of a quart, drive it around and measure again. I try to stay up towards the top of the meter and not the bottom. I also never add a whole quart even if it's all the way down. There is fluctuation in the measurement system but it will give you a pretty good idea of where you're at. Just don't go dumping in a fu quart and overfill. Too much is worse than a little low.

 

What you're experiencing is slight expansion from the oil being HOT. Once it cooled, it condensed a bit and read one notch lower.

Like others have said, it's better to have a little more than a little less. I run mine so that it's 3 notches below the "top bar" that says "this is enough", if you will

 

There are 2 things that affect the oil level in the pan that the sensor can read:
1) The oil temp (hot or operating, and old from sitting overnight) - hot oil is thinner, more fluid (drains out of the engine faster) but slightly more volume, cold oil is more viscous and drains slower, and is lesser in volume.

2) Time since engine shut off - every minute after shutoff, incrementally more of the oil drains out of the engine into the pan ,slightly increasing the level (to a point).


The sensor switches from one bar to the next bar at some level - if the level of the oil is right near that change-over level, then the oil being hot or cold, or draining 6 minutes post engine shutoff, vs draining 2 hrs after engine shutoff, can make enough of a difference to illuminate another bar .

But thats not an actual problem. The goal is to get the oil in the middle of the range and then stop obsessing about it. Above the min mark is sufficient - more doesn't help. Going above the max mark IS a problem (overfill).

Let the system measure the oil level, if you are in the middle of the range of values, leave it be and get on with life. If its at the bottom mark, add enough oil to get it into the middle of the range, and leave it be and get on with life.

 

I'll trade the electronic oil measuring system for a dipstick anyday. Hehehe