Oil Check, Differnt Readings???
 

I got my oil changed recently when i got home the oil was at the upper mark of the dipstick, i've checked it a couple of times and get differnt readings, somtimes at the top mark and others half way in between marks? Car is always level and warmed up running after a run, the level gauge always comes back to the same spot. I know the gauge is not worth a damn but it is there. It seems i get the loer reading after a run to the market and back, early evening cooler out, about 8 mile round trip. I know not to keep the level up to the upper mark on the dipstick, just wondering why i would get the different readings, after a spirited longer outing it seem to be back up to the top mark. I don't fully understand the dry or wet sump system.

"warmed up" isn't enough. Yes, the car must be level, and the car must be idling, but the front cooler must also be hot to the touch, which means that the entire oiling system is in the game. If you check the oil before the front cooler thermostat opens it will skew your readings... If you're consistent with the temperature, it's impossible to get inconsistent readings :).

if the engine, 83 911sc cab, is not up to full operating temp, i went 4 mile one way stopped in the market and back 4 miles, the temp gauge was up to the first mark, which is normal for this car, but perhaps after the short round trip, if it in fact was not fully upto full operating temp would this cause for a lower reading on the dip stick? or should be higher on the dipstick, not sure on this one, perhaps more oil is in the engine and not circulating fully through the entire system, thefore not reading an accurate reading at the side holding tank where the dipstick is located? thanks