Too much oil means that it gets into the crankcase breather and cannot breathe. Plus if that gets blocked you get oil everywhere where it should not be, e.g. intake tracks.

So overfilling is worse than being slightly under.

 

So because you got away with it, great, should others just ignore... guess its their gamble.

Me OCD, no.... master mechanic with an automotive engineering degree having worked with some race teams... so the stereo type doesn't fit here. If you had a mechanical dip stick instead of the unreliable and in accurate electronic system you would be better to judge the degree of over fill.

Anyway its your car, your money you can do what you want but suggesting to others this is fine is irresponsible

 

Biggest issues as far as I know with overfilling engine oil is the possible rapid degradation of the catalytic converter.

 

+1 thanks for sharing

 

I changed the oil in my 911. Yellow overfill light came on after driving about 100 miles. I drove back home and it went back out. never came on again. So I guess I am ok ?

 

Blackstone Labs has a small pump used to extract an oil sample. Put the hose in and screw a sample bottle onto the pump. Pull the plunger back and you get a 100 ml sample in the bottle. Clean and easy. For an overfill take out an sample or two.

 

So as a master mechanic you are ok with untrained owners snaking tubing down into the motor ? If any of that tubing falls off then that's a real problem. Again there are two stages of warming lights, yellow and red. I was told the yellow is triggered from 200 cc-800cc overfill from an authorized tech. I was also told at those levels no damage occurs. Bottom line is the sensor is way too sensitive.

 

I never mentioned what approach to take in removing the oil BUT it is a common one and it is only snaking into the oil tank so not the engine, it would need to pass the oil filter to become a problem.

So you agree the oil level system is flawed....

Any I have made my point. Merry Christmas all.

 

Here is how it goes for most.
Operator gets “low oil light”
Operator fills less than one quart
Operator gets the “yellow” overfill light either immediately, days, weeks, or moths later

Now my point is by going from a low oil light and adding one quart or less and then getting the “yellow” overfill light is nothing to worry about.

If I am missing something from this logic please explain.

 

I don't know how it goes for most, but I know that some of us check the oil level frequently enough to notice when it is low, before any warnings appear, and we then add 200ml. If it still reads below the full mark, then we add another 100 or 200ml.

I've got 6800 miles on my car and have never seen a oil level warning.

.

 

Here is my two cents. Fill with 7 Qts and check the fill level. You will be at the bottom line, now add 2oz and you will be at the optimum level. If you do overfill crack the filter and let out a small amount to lower level.

 

Even with 7l I got overfill light.

If no oil change but just oil top off due you yellow OK to drive to Red not OK to drive it's always OK if you don't put in more than 400cc and get the overfill light for a few sessions.

I now only add 200cc at the time.

Memo to self; buy leather oil bottle holder that velcro's in frunk, tomorrow when I pick up the car..

 

The window from underfill to overfill is way too small on the new cars... Way too easy to overshoot... Small volume additions as Pete suggests. That way, if you overfill it will be by a small amount and if you overfill just drive flat out, Trakcar style and problem solved! Whilst a pretty simple idea, not sure I would snake tubing into my oil tank, just in case...

 

Removing the oil filter drops around 0.5qt. Been my solution to the dreaded overfill light.

Another tip, from a Porsche tech friend, is to leave the rear hatch open while warming up the oil/checking the level. Seems to speed up the reading.

 

If I'm reading the OP's post correctly, the tube for his siphon pump was snaked into the crankcase not the oil tank, which has been referenced in a couple of posts. Unless I'm mistaken, there's no easy way to get a tube into the oil tank on the 991 GT3. The chances of the tube coming loose or getting stuck may be acceptably low but if it does happen it will be in the engine.