996 C4S fluctuating oil level

Hi all, New to 911 ownership, picked up a 996 C4S 2 weeks ago and have fallen in love! However, having a very odd problem with my oil level. I am finding that the oil level is fluctuating. I am finding this both when hot and cold in the same spot (garage) and I am measuring on the dipstick. It seems when the engine has been run for a continued amount of time and the oil is very hot, more will drain through and i get just under maximum the the morning after on the dipstick. When I do a short 15 min run and I check the next morning it will be just over 3/4 full on the dipstick. Any ideas what would cause this?

There's many parts on the engine that can hold oil like hydraulic lifters. Depends how much is in them, etc.

My C4S does the same too, garage says it's fine. Hasn't worried me in my couple of years of ownership.

Sounds normal to me . ign on but engine not started .. the oil pressure gauge should read at 0 .. anything above that and the sender unit is faulty . To check the oil lvl .. engine oil at 90 degrees ( operating temp ) .. 1 min countdown on the cluster display ( ign on only ) then see how many segments you are down .. it's always best to be at least x1 segment down from max . Ign on / off will give you the countdown .. if not 1 min then it's not hot enough . Oil expands with heat so you need it hot ( if not hot enough or even too hot you will have a different lvl ).. the above check is the standard mode of checking ... it's how i do it anyways . Each segment is approx 0.2 of a ltr .. the engine holds approx 10.5 ltrs with min to max being about 1.5 ltrs .. in other words even at min lvl you have plenty of oil in the engine , there is a seperate warning light if the pressure falls too low . You can use the dipstick if you wish .. i find it hard to actually see a lvl on it so use the gauge .. it's pretty accurate shall we say .

I used the gauge today when filling up with fuel, oil showed bang in the middle, so three bars from maximum - stick .6 of a litre in, or better to put .5 in to avoid any slight overfill?

Sorry, just read your post again- .4 it is.

The point as a mechanic that i'm making is that there is a huge amount of oil in the engine .. even at min lvl there is still about 9.0 litres of oil in the engine.. 0.4 in your case won't make a difference .. i know its a gauge and it has to be correct but to be a segment or 3 down is better than an over fill and will make no difference to the engine . one segment down from the top is best but as its difficult to get it exact then if at max then its fine .. if about 0.2 over its fine .. start getting to 0.5 and over and you might start to get some smoking from the tail pipes . i've seen 2-3 ltrs overfilled in my time .. yup they smoked but still ran .. to be fair that was newer models .. Cayennes etc as it's easy to over fill these cars . In short .. and i know i'm a mechanic , i'm not an owner .. but don't worry to much about it being exact. If you are so low on oil that the car is worried .. you will get a red light saying so Honest answer !